İstanbul Üniversitesi
Research Laboratories Information System
Research Laboratories Information System
İleri Litografik Yöntemler Laboratuvarı
İleri Litografik Yöntemler Laboratuvarı
İstanbul Üniversitesi, Fen Fakültesi, Fizik Bölümü, İleri Litografik Yöntemler Laboratuvarı, Vezneciler, Fatih/İstanbul, 34134
Toplam kullanılan BAP Kaynağı: 317.764,00 TL
Temiz oda, mikro ve nano boyutlarda fabrikasyon, görüntüleme ve yapısal karakterizasyon işlemlerine olanak vermektedir.
Kalkınma Bakanlığının altyapı projesi olarak 2014 yılında kurulumu tamamlanmış olan İleri Litografik Yöntemler Laboratuvarı, 100 m2 alanda 10, 100 ve 1000 sınıfı temiz oda ortamında, elektronik/optoelektronik aygıtların nano/mikro boyutta fotolitografik ve kuru aşındırma teknikleriyle fabrikasyonu, nanolitografi, katıların yüzey ve kesitlerinin nanometre skalasında görüntülenmesi, malzemelerin bileşimlerinin belirlenmesine yönelik araştırmalar yapılmasına uygun donanıma sahiptir.
100 sınıfı sarı odada fotolitografi prosesi donanımı: (10 sınıfı laminar akışlı, döndürerek kaplama, sıcak tabla, ultrasonik temizleyici kimyasal tezgâh, Maske hizalayıcı, termal buharlaştırma sistemi, profilometre), kuru aşındırma prosesi donanımı (Odaklanmış iyon/elektron demeti), Görüntüleme cihazları (SEM, AFM), malzeme bileşimi tayini (EDS).
İstanbul Üniversitesi, Fen Fakültesi, Fizik Bölümü, İleri Litografik Yöntemler Laboratuvarı, Vezneciler, Fatih/İstanbul, 34134
Toplam kullanılan BAP Kaynağı: 317.764,00 TL
Advanced Lithographic Techniques Laboratory
Istanbul University, Faculty of Science, Department of Physics, Advanced Lithographic Techniques Laboratory, Vezneciler, Fatih/Istanbul, 34134
Total resource (BAP): 317.764,00 TL
Clean room enables micro and nano-sized fabrication, structural characterization and their imaging process.
Laboratory of Advanced Lithographic Methods, founded in 2014 as an outcome of Ministry of Development-funded infrastructure project, is suitably equipped to enable studies fabrication of electronic/optoelectronic devices by photolithographic and dry etching techniques at a nano/micro scale, and nanolithography, nanometric imaging of surfaces and sections of solids, and
determination of elemental composition of materials in an area of 100 m2 in Class 10, 100 and 1000 clean rooms.
Photolithography process equipment: (Class 10 laminar flow, rotary coater, hot plate, ultrasonic
cleaning chemical bench, Mask aligner, thermal evaporation system, profilometer), dry etching equipment (focused ion/electron beam system) in Class 100 yellow room, Imaging devices (SEM, AFM), determination of elemental composition of materials (EDS).
Istanbul University, Faculty of Science, Department of Physics, Advanced Lithographic Techniques Laboratory, Vezneciler, Fatih/Istanbul, 34134
Total resource (BAP): 317.764,00 TL
| Görev | Ünvan | Ad | Soyad | Dahili Telefon | AVES Link | |
|---|---|---|---|---|---|---|
| Cihaz Sorumlusu | ARAŞTIRMA GÖREVLİSİ | GÖKSENİN | KALYON | CV | ||
| Cihaz Sorumlusu | DOKTOR ÖĞRETİM ÜYESİ | MUSTAFA | AYDIN | CV | ||
| Cihaz Sorumlusu | DOKTOR ÖĞRETİM ÜYESİ | SELMAN | MUTLU | CV | ||
| Cihaz Sorumlusu | DOÇENT | FURKAN | KURUOĞLU | CV | ||
| Cihaz Sorumlusu | DOÇENT | FAHRETTİN | SARCAN | CV | ||
| Lab Sorumlusu | PROFESÖR | ÖMER | DÖNMEZ | CV | ||
| Lab Sorumlusu | PROFESÖR | AYŞE | EROL | CV |
pp12pp
Cihaz Adı : Wire Bonder
Marka : TPT
Model : HB05
Teknik Özellik : Altın " Wedge Bonding" ve "Ball Bonding" yapılabilmektedir. Altın tel çapı 25 mikrometre.
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Oksijen Plazma Temizleyici
Marka : Diener
Model : ZEPTO
Teknik Özellik : 2,6 litrelik yüzey temizleme, yüzey aktivasyonu, yüzey aşındırma ve yüzey biriktirme için kullanılan bir plazma sistemidir.
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Güç Kaynağı
Marka : Keithley
Model : 2601
Teknik Özellik : Source ±DC voltage : 1?V to 40.4V Source ±DC current : 1pA to 3.03A1 Measure ±DC voltage : 1uV to 40.8V Measure ±DC current : 1pA to 3.06A
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Helyum Kaçak Tespit Dedektörü
Marka : Pfieffer Vacuum
Model : HLT550
Teknik Özellik : Vakum Modu Algılanablir Maksimum Kaçak Değerleri : He4 : 1 mbar l/s H2, He3 : 1×10-2 mbar l/s Sniffing Modu Algılanablir Maksimum Kaçak Değerleri : He4 : 1 mbar l/s H2, He3 : 1×10-2 mbar l/s
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Güç Kaynağı
Marka : Keithley
Model : 2400C
Teknik Özellik : Max. Output Power: 22W, four quadrant source or sink operation. Source/Sink Limits: 2400, 2400-C: ±1.05A @ ±21V, ±105 mA @ ±210V. 2400-LV: ±1.05A @ ±21V. Current Regulation: Line: 0.01% of range. Load: 0.01% of range + 100pA. Voltage Limit: Bipolar voltage limit (compliance) set with single value. Min. 0.1% of range. Overshoot: <0.1% typical (1mA step, RL = 10k?, 20V range).
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Turbomoleküler pompa
Marka : Pfeiffer
Model : Hicube 80 Clasic
Teknik Özellik : 230 V, 50-60 Hz
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Rotary Pompa
Marka : Pfeiffer
Model : Duo 3
Teknik Özellik : 115W, 50-60 Hz,
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Lock-in Amplifier
Marka : STANFORD
Model : SR830
Teknik Özellik : 100 kHz, >100 dB dynamic reserve, 0.01 degree phase resolution
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Sıvı Azot Üretim Cihazı
Marka : Kelvinic
Model : M280
Teknik Özellik : Üretim : 40-50 Lt/gün Kapasite : 120 Lt Buharlaşma Oranı : <0,8% /gün
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : PMT Soğutma Sistemi
Marka : Hamamatsu
Model : 994002
Teknik Özellik : Temperature rage -70 oC -90 oC
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Photomultiplier
Marka : Hamamatsu
Model : R3896 Photomultiplier Tube, C9525-01 Power Supply, C6270 Divider and Amplifier Unit, C9143 Cooler
Teknik Özellik : Spektral Duyarlılık : 185 - 900 nm Maksimum Duyarlılık Aralığı : 450 nm Malzeme : Multialkali Minimum Etkin Alan : 8x24 mm Pencere Malzemesi : UV Cam
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Yüksek Voltaj Pulse Jeneratörü
Marka : Avtech
Model : AVRZ-5W-B-INV
Teknik Özellik : 15 ns-10 micro s , 5kHz
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Düşük Akım / Güç Kaynağı
Marka : Keithley
Model : 2635 A
Teknik Özellik : 30.3 W per channel maximum ± 20.2 V @ ± 1.5 A ± 202 V @ ± 100 mA
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Switch System
Marka : Keithley
Model : 7001
Teknik Özellik : Signals : Four 3-pole rows Maximum Voltage : 250V DC, 250V rms, 350V AC peak, signal path to signal path or signal path to chassis . Maximum Current : 1A peak
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Güç Kaynağı
Marka : Keithley
Model : 2601
Teknik Özellik : Source ±DC voltage : 1uV to 40.4V Source ±DC current : 1pA to 3.03A1 Measure ±DC voltage : 1uV to 40.8V Measure ±DC current : 1pA to 3.06A
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Osiloskop
Marka : Lecroy
Model : 715Zi
Teknik Özellik : 1.5 GHz Bandwidth, 4 input channels. 20 GS/s on 2Ch Max
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Isıtıcı
Marka : VELP Scientifica
Model : REC Digital Heating Ceramic Plate
Teknik Özellik : 0-550 oC, Digital
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Isıtıcı
Marka : VELP Scientifica
Model : RC
Teknik Özellik : 0-370 oC,
Miktar : 3
Cihaz Kaynağı : DiğerCihaz Adı : Chiller
Marka : Gazi
Model : ER 1.0 Serisi
Teknik Özellik : 2500 kcal/h/2.9 kW soğutma kapasitesi.
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Mikroskop Kamerası
Marka : Kameram
Model : A 640 – 122 CU
Teknik Özellik : 3.2 Megapiksel renkli digital
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : ISI BUHARLASTIRMA FILM KAPLAMA SISTEMI THERMAL EVAPORATÖR
Marka : VAKSİS
Model : Özel Model
Teknik Özellik : 1 Çift odacıklı 3 elektrotlu bilgisayar kontrollü sistem, metalizasyon işlemini gerçekleştirmektedir
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : ODAKLANMIS IYON VE ELEKTRON ISINI ELEKTRON MIKROSKOBU
Marka : FEI
Model : VERSA 3DLOVAC
Teknik Özellik : Sistem Odaklanmış iyon demeti ve taramalı elektron mikroskobu ile bütünleşiktir. ikili demet sistemi, malzemelerin yüksek çözünürlükte, 2D ve 3D karakterizasyonunda, nano fabrikasyon çalışmalarında kullanılmaktadır.
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : UV MASKE HİZALAYICI
Marka : SÜSS MİCROTEC
Model : MJB4
Teknik Özellik : Litografide maske hizalayıcı olarak ve örnek üzerindeki fotorezist materialini UV ışığa istenilen süre kadar maruz bırakmak amacıyla kullanılır. Kontak, Hard, Soft, Vakum ve düşük vakum modları vardır. 5 saniye UV ışığa maruz bırakma ve 5 saniye bekleme süresi bulunmaktadır.
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : Ultra Saf Su Cihazı
Marka : SARTORİUS
Model : belirtilmemiştir
Teknik Özellik : Temiz oda sistemi ile entegre
Miktar : 1
Cihaz Kaynağı : DiğerCihaz Adı : MEKANIK PROFILOMETRE
Marka : KLA Tencor
Model : P6 Profilometer
Teknik Özellik : Cihaz, yüzeyin topografisini 3D olarak belirlemektedir. Bu cihaz ile yüzey pürüzlülüğü, yüzeydeki basamak derinliği, dalgalanma gibi parametreler elde edilir. Pürüzlülük derinliği ile malzemenin aşınma miktarı hakkında bilgi edinilebilir
Miktar : 1
Cihaz Kaynağı : Diğer
- Makale & Yayın (40)
- Sanayi İşbirliği (1)
- Patent (3)
- Dış Kaynaklı Çalışma (0)
- Faydalı Model (0)
- Ticarileşme (0)
- Proje (6)
pp12pp
- Adı : Enhancement of light emission characteristic of a GaAs-based Gunn light emitting diode with a quasi-cavity
Açıklama : We report on a novel GaAs-based quasi-cavity enhanced Gunn light emitting diode (GLED) with a planar architecture operating at around 876 nm. GLED device was fabricated using an n-type GaAs epilayer with and without bottom 20 pairs of Al0.1Ga0.9As/AlAs distributed Bragg reflectors (DBRs) to investigate the influence of the incorporated bottom DBRs on emission characteristic of the Gunn device. The devices start emitting when Gunn oscillations with a frequency of 1 GHz emerges at the negative differential resistance (NDR) threshold at 3 kV/cm. Light intensity-electric field characteristic of both GLEDs with and without DBRs shows an abrupt increase in emitted light intensity at NDR threshold. The full-width at half maximum (FWHM) of the electroluminescence (EL) spectrum is reduced from 30 nm to 14 nm, and emitted light intensity is enhanced by about four times of magnitude compared with the GaAs-GLED without a quasi-cavity. The period of Gunn oscillations is found to be 1ns (f = 1 GHz). Divergence of the emitted light from GaAs-GLED with a quasi-cavity is found to be lower than that from basic GaAs-GLED device. EL mapping images prove that as increasing applied electric field, EL intensity enhances and spans almost the whole sample surface with a higher intensity in the vicinity of the anode of the device as an indication of growing and propagating Gunn domain along the device. Our results reveal that the GLED with a quasi-cavity operates with a higher spectral purity. DOI: 10.1016/j.mssp.2023.107877
Ekip : Selman Mutlu, Goksenin Kalyon, Fahrettin Sarcan , Omer Goksel Erbas, Ayse Erol - Adı : Band Profile and Surface Acoustic Wave Attenuation Analysis of Polygonal Cavity-type Piezoelectric Phononic Crystals
Açıklama : In this study, we examined the dispersion profiles and surface acoustic wave attenuation properties of polygonal cavity-type phononic crystals in relation to changes in the number of vertices. Both band analysis and transmission spectrum calculations are performed using finite element method simulations. The findings indicate an increase in the number of vertices of phononic crystal results in an increase in local resonance bandgap frequencies and corresponding transmission peaks. Furthermore, the phononic crystal bandgap widens from 7.3 MHz to 11.1 MHz as the number of vertices increases from 3 to 14, as demonstrated by the obtained dispersion profiles. Comparable features are observed in the transmission spectra for alternating polygonal cavity-type phononic crystal periodic grooves. Additionally, the ability of the surface acoustic wave attenuation is affected by the phononic crystal shape, and the resonance frequency of the phononic crystals can be adjusted by changing the number of vertices. DOI:10.26650/PAR.2023.00003
Ekip : Furkan KURUOĞLU, Nurseli Seda GENÇ, Ayşe EROL, Ahmet ÇİÇEK - Adı : Effects of annealing temperature on a ZnO thin film-based ultraviolet photodetector
Açıklama : In this paper, the effects of annealing temperature on the performance of a ZnO thin film-based Metal-Semiconductor-Metal (MSM) type ultraviolet (UV) photodetector is reported. ZnO thin films were grown on a glass substrate using the Pulsed Filtered Cathodic Vacuum Arc Deposition (PFCVAD) technique at room temperature and after the deposition process the samples were annealed at 400, 450 and 550 °C in air condition to investigate the annealing effect on the structural, electrical, and optical properties of the photodetector. ZnO thin films which have grains in nanometer range has an increasing in the diameter of grains from 10.5 to 18.3 nm as a function of annealing temperature results in a red shift in the cut-off wavelength of the photodetector from 3.25 eV (381 nm) to 3.23 eV (383 nm). It is demonstrated that the sensitivity and the speed (rise/fall times) of the ZnO thin film based MSM photodetectors enhances with increasing post growth annealing temperature of ZnO thin film due to the increase in the absorption coefficient and the decrease of the total area of the grain boundaries due to the larger grain sizes formation in ZnO thin films with increasing thermal annealing temperature. DOI: 10.1088/1402-4896/ac4634
Ekip : Ümit Doğan, Fahrettin Sarcan, Karamuran Kara Koç, Furkan Kuruoğlu, Ayşe Erol - Adı : Determination of electronic band structure of quaternary ferromagnetic Ga0.97-yMn0.03CryAs epitaxial layers
Açıklama : Introducing transition metals to conventional III-V semiconductors anomalously changes their fundamental characteristics, such as electronic, magnetic, and structural properties. In this study, we show that the valence band anti-crossing (VBAC) model can be exploited to calculate the electronic band structure of the quaternary Ga0.97-xMn0.03CrxAs epitaxial layers. In this model, the localized Mn and Cr defect states interact with the valence band states (VB), reconstructing VBs and splitting each VB state. The splitting top of the VB state forms an impurity band (IB) and fundamental VB edge. Photomodulated reflectance (PR) spectroscopy is exploited to determine optical transition energies at room temperature. PR spectra were analyzed with the third derivative functional form (TDFF) signal's line shape. The experimental optical transition energies, including band-to-band and spin split-off band transitions, match the calculated optical transition energies by the VBAC model. In the calculation, the interaction energy between localized Mn/Cr-energy level and valence band edges is experimentally determined as 0.7 eV. DOI:10.1016/j.physb.2023.415074
Ekip : Omer Donmez, Mustafa Gunes, Mohamed Henini and Ayse Erol - Adı : Selective Antimicrobial Properties of W-Ge Nanocomposite Thin Films
Açıklama : The antimicrobial properties of W-Ge nanocomposite thin films as a function of Ge concentration were investigated within the scope of this study. The films were deposited on an AZ61Mg substrate using a magnetron sputter source with a co-deposition technique. Structural analyses showed that all coatings had a composite crystal structure. Additionally, the morphological investigation indicated that films had goosefoot-type structures at low Ge concentrations (5% and 10%), while Ge-rich films (40% and 60%) had cauliflower-type structures. The 20% Ge concentration coating had both structures. Regarding the surface morphology, the root mean square roughness of the surface reached its maximum value at a Ge concentration of 60% while the surface roughness and wettability of all the films showed an opposite trend. The antimicrobial activity of the W-Ge nanocomposite films against gram-negative (Salmonella typhimurium NRRLE 4413, Escherichia coli ATCC 25922) and gram-positive (Staphylococcus aureus 6538 P., Bacillus subtilis IM 622) bacteria was investigated via disc diffusion antibiotic sensitivity assay. Based on the antibacterial activity test, it was concluded that although all the films had antimicrobial efficiency against gram-negative and gram-positive bacteria, they were more effective against gram-positive bacteria. Moreover, with the increased surface roughness of the films, the number of grain boundaries, which cause an increase in the intensity of the oxide phases of the metals, increases, resulting in better antibacterial activity. DOI:10.26650/PAR.2023.00005
Ekip : Selçuk Atasoy, Yasin Kurul, Sıtkı Aktaş, Fahrettin Sarcan, Mustafa Şükrü Kurt, Adnan Ayna, Ekrem Darendelioğlu, Ayşe Erol - Adı : Fabrication of CdS nanospheres based hybrid solar cells having increased efficiency
Açıklama : The impact of surface modification through diverse dyes (Eosin-Y, D205, N719 and N3) on structural, morphological, optical, and electrical properties of CdS/P3HT hybrid solar cells is studied. X-ray diffraction (XRD) pattern shows that CdS nanospheres have a hexagonal structure with a preferential orientation of (002) with respect to indium tin oxide (ITO) coated glass slide. Scanning electron microscopy (SEM) results indicate that compact and dense spherical morphologies of CdS occurred, and the P3HT layer also consisted of small spherical grains. The bandgap of CdS is found to be 2.52 eV according to Tauc’s plot analysis. Absorption spectra demonstrate that interfacial modification via each dye leads to an increase in the absorption in the wavelength range of 300–1000 nm. DOI: 10.1007/s00339-022-05317-2
Ekip : S. Yılmaz, A. Ünverdi, M. Tomakin, İ. Polat, E. Bacaksız - Adı : Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam
Açıklama : Focused ion beam (FIB) is an effective tool for precise nanoscale fabrication. It has recently been employed to tailor defect engineering in functional nanomaterials such as two-dimensional transition metal dichalcogenides (TMDCs), providing desirable properties in TMDC-based optoelectronic devices. However, the damage caused by the FIB irradiation and milling process to these delicate, atomically thin materials, especially in extended areas beyond the FIB target, has not yet been fully characterised. Understanding the correlation between lateral ion beam effects and optical properties of 2D TMDCs is crucial in designing and fabricating high-performance optoelectronic devices. In this work, we investigate lateral damage in large-area monolayer WS2 caused by the gallium focused ion beam milling process. Three distinct zones away from the milling location are identified and characterised via steady-state photoluminescence (PL) and Raman spectroscopy. The emission in these three zones have different wavelengths and decay lifetimes. An unexpected bright ring-shaped emission around the milled location has also been revealed by time-resolved PL spectroscopy with high spatial resolution. Our findings open up new avenues for tailoring the optical properties of TMDCs by charge and defect engineering via focused ion beam lithography. Furthermore, our study provides evidence that while some localised damage is inevitable, distant destruction can be eliminated by reducing the ion beam current. It paves the way for the use of FIB to create nanostructures in 2D TMDCs, as well as the design and realisation of optoelectrical devices on a wafer scale. DOI:10.1038/s41699-023-00386-0
Ekip : Fahrettin Sarcan, Nicola J. Fairbairn, Panaiot Zotev, Toby Severs-Millard, Daniel J. Gillard, Xiaochen Wang,, Ben Conran, Michael Heuken, Ayse Erol, Alexander I. Tartakovskii, Thomas F. Krauss, Gordon J. Hedley and Yue Wang - Adı : Comprehensively analysis of hot electron transport in as-grown and thermally annealed n-type modulation-doped Al0.15Ga0.85As/GaAs0.96Bi0.4 quantum well structure
Açıklama : We report experimental and analytical results on hot electron transport in as-grown and thermally annealed n-type modulation-doped Al0.15Ga0.85As/GaAs0.96Bi0.4 quantum well (QW) structures at room temperature. The drift mobility of as-grown and thermally annealed samples is 2265 and 1414 cm2/Vs at a low electric field region, respectively. The lower electric field electron mobility for the thermally annealed sample is due to the increased 2D electron density following the annealing process. The drift velocity ( ) of the as-grown sample tends to saturate at 6.1 × 106 cm/s, contrary to the thermally annealed sample, for which no saturation is observed. The of the annealed sample is also lower due to the higher 2D electron density caused by annealing. Analyzing the experimental results concerning the theoretical model reveals that i) hot electron transport occurs in parallel mode due to the presence of electrons in both Al0.15Ga0.85As (barrier) and QW layers, ii) hot electrons transferred from QW to the barrier layer via so-called real space transfer (RST) mechanism is suppressed at higher electric fields even though the lower energy barrier between the barrier and QW layers, and iii) transfer of electrons from QW (-valley) to the nearest L-valley, inter-valley transfer (IVT), dominates on the hot electron transfer at higher electric fields even with a higher energy barrier. DOI:10.1016/j.mssp.2022.107227
Ekip : Omer Donmez, Mustafa Aydın, Selman Mutlu, Janne Puustinen, Joonas Hilska, Mircea Guina, Ayse Erol - Adı : Surface acoustic wave quasi-Bessel beams generated by symmetrically tilted interdigital transducers
Açıklama : Formation of surface acoustic wave (SAW) quasi-Bessel beams on a piezoelectric substrate through superposition of plane waves generated by interdigital transducers tilted symmetrically about the propagation axis is numerically and experimentally demonstrated. Acting as an axicon, the tilted transducers provide a facile way for quasi-Bessel beam generation. Finite-element method simulations reveal that non-diffracting Bessel beams, whose length and width are 193 and 1.38 wavelengths, respectively, can be obtained on a YX-128∘ lithium niobate substrate for an axicon angle of 15 degrees. The corresponding values for 20 degrees are 146 and 1.05 wavelengths, respectively. For a wavelength of approximately 300 micrometers, transmission spectra show that Bessel beam formation can be achieved at frequencies around 13.3 MHz. Bessel beam is visualized through a thin liquid film of methanol on the substrate. SAW Bessel beams can be utilized in acoustophoresis in microfluidic systems and sensing applications. DOI 10.1088/1361-6463/ac570c
Ekip : Bülent Uluğ, Furkan Kuruoğlu,Yeşim Yalçın, Ayşe Erol, Fahrettin Sarcan, Ali Şahin, Ahmet Çicek - Adı : Analysis of mixed optical transitions in dilute magnetic AlAs/GaAs/GaMnAs quantum wells grown on high substrate index by molecular beam epitaxy
Açıklama : In this study, we report the influence of high-index substrate orientation on the optical properties of dilute Mn containing a single quantum well (QW) structure grown by molecular beam epitaxy (MBE). The electronic band structure of the samples is calculated with finite element methods (FEM). Photomodulated reflectance (PR) spectroscopy is employed to determine the optical transition energies at room temperature. PR experimental results are analyzed with the Third Derivative Functional Form (TDFF) signal function. TDFF fitting shows that the optical transition starts below the fundamental GaAs bandgap energy for the samples grown on (3 1 1) B and (4 1 1) B-oriented substrates. Comparing TDFF fitting and calculated optical transition energies with FEM show that the optical transition occurs in type-I and type-II as direct and indirect transitions, respectively. Type-I and -II optical transitions are addressed concerning the electronic band structure of the sample grown on oriented substrates. DOI:10.1016/j.mseb.2023.116349
Ekip : Shemshat Kerimova, Omer Donmez, Mustafa Gunes, Furkan Kuruoglu, Mustafa Aydın, Cebrail Gumus, Ayse Erol - Adı : High-Field Electron-Drift Velocity in n-Type Modulation-Doped GaAs0.96Bi0.04Quantum Well Structure
Açıklama : The drift velocity (vdrift) of electrons in an n-type modulation-doped GaAs0.96Bi0.04/Al0.15Ga0.85As quantum well (QW) structure is determined for electric fields (F) ranging from ≈0.4 to 3.58 kV cm−1. The resulting vdrift characteristic exhibited a linear increase and reached ≈6 × 106 cm s−1 at low electric fields then almost saturated with increasing electric field. The electron drift mobility is determined as 2265 cm2 Vs−1 in the regime where the drift velocity is linear with respect to the electric field. The drift velocity saturates at ≈6.1 × 106 cm s−1 at the electric fields between ≈2.7 and 3.4 kV cm−1. Saturation of the drift velocity is attributed to the transfer of the electrons from the QW layer (GaAs0.96Bi0.04) with higher electron mobility to the barrier layer (Al0.15Ga0.85As) and satellite valley L-valley with lower electron mobility, which initiates cooling of electrons via phonon scattering in the sample. DOI: 10.1002/pssr.202200204
Ekip : Mustafa Aydın, Selman Mutlu, Ayse Erol, Janne Puustinen, Joonas Hilska, Mircea Guina, Omer Donmez - Adı : InGaAs-based Gunn light emitting diode
Açıklama : We report an n-type In0.53Ga0.47As based Gunn light emitting diode operated at around 1.6 μm. The device structure comprises of an n-type In0.53Ga0.47As epilayer with a thickness of 5 μm grown by Metal Organic Vapour Phase Epitaxy (MOVPE) on a semi-insulating InP substrate and fabricated in a planar architecture with a stepped structure at anode side to suppress the destructive effect of high built-in electric field in propagating Gunn domain. Gunn diode is operated under pulsed voltage with a pulse width of 60 ns and pulse duration of 4.5 ns to keep the duty cycle as low as 0.0013%. The Gunn oscillations with an 1 ns period are observed at around 4.1 kV/cm, which corresponds to the electric field threshold of Negative Differential Resistance (NDR). The light emission at around 1.6 μm also starts at the threshold electric field of the NDR region (E = 4.2 kV/cm) of the current-voltage curve, and the emission intensity increases drastically with increasing applied electric field. The observed light emission at NDR threshold electric field where Gunn oscillations appear on the voltage pulse is attributed to the impact ionisation process occurring in the current domains along the sample, which generates excess carriers to initiate the band-to-band recombination in In0.53Ga0.47As. DOI:10.1016/j.mssp.2023.107389
Ekip : G. Kalyon, S. Mutlu, F. Kuruoglu, I. Pertikel, I. Demir, A. Erol - Adı : Determination of band tail widths in MOCVD grown InGaN single layer within GaN based p-i-n LED structure through photo-induced measurements
Açıklama : Within a p-i-n LED structure, energy band gaps of MOCVD grown %10 In content InGaN and GaN layers were obtained through traditional UV–Visible transmission-absorption measurements and utilizing surface photovoltage (SPV) and spectral photoconductivity (SPC) measurements. Moreover, all applied techniques determined that the total band offset between InGaN and GaN layers were around 0.3–0.4 eV. Furthermore, the temperature dependence of band gaps of each InGaN and GaN layer was analyzed through a modified Varshni relation where both Varshni coefficients and band tail energy width were explored. Band tails in a modified Varshni relation, SPV and SPC measurements were in agreement with each other and originated Franz-Keldysh Effect attributed to the presence of photon assisted tunneling. DOI:10.1016/j.jlumin.2022.119543
Ekip : Orhan Özdemir, Kutsal Bozkurt, Neslihan Ayarcı Kuruoğlu, Hanife Baş, Fahrettin Sarcan, Ayşe Erol, Bandar Alshehri, Karim Dogheche, Elhadj Dogheche - Adı : Dielectric Response and Capacitance Measurements of Ag/ PVAc-Si /p- Si Structure
Açıklama : In this study, the efect of Poly(vinyl acetate) latex with Silicone surfactant (shortly PVAc-Si) thin flm on the dielectric and capacitance-voltage properties of Ag / PVAc-Si /p-Si (MIS) structure were investigated. The dielectric characterization was obtained by impedance spectroscopy technique between 40 Hz-110 MHz at room temperature. The capacitance-voltage measurements were performed to clarify the fat band voltage of the sample. The frequency dependence of the real and imaginary parts of the complex impedance function indicated a space charge polarization. The Nyquist plots confrmed a single Debye type relaxation. The real and imaginary components of the complex dielectric function implied the efect of the grain and grain boundary efects in the material. Alternative current (ac) conductivity versus frequency curve of the structures displayed two diferent conductivity regimes. Nearly dc conductivity for the low frequencies and the dispersive region of the high-frequency band was obtained. The increase in ac conductivity with increasing frequency has been explained in the context of the Quantum Mechanical Tunneling (QMT) mechanism for PVAc-Si flm-induced devices. According to the capacitance-voltage measurement, it is also shown that there is a hysteresis for fat band capacitance in between the applied forward and reverse voltage. Reduction of this hysteresis is achieved by the applied voltage across terminals of the PVAcSi flm-induced MIS structure. This controllable reduction in hysteresis may fnd a place in an application for foating gate memory devices. This study also provides to understand the efect of insulator layer thickness on the dielectric behavior of MIS devices. DOI:10.1007/s12633-022-01758-9
Ekip : Banu Süngü Mısırlıoğlu · Duygu Gülşen · Furkan Kuruoğlu · Murat Çalışkan · Ayfer Sarac Ozkan · Merih Serin - Adı : Relation between thermal quenching of photoluminescence and negative capacitance on InGaN/GaN multiple quantum wells in p-i-n structure
Açıklama : Temperature-dependent photoluminescence (PL) and surface photovoltage (SPV) measurements were carried out to detect radiative and non-radiative transitions on InGaN/GaN quantum well (QW) blue light-emitting device (LED). The emissions, peaking at 3.03 eV and 2.89 eV, were present in both PL and SPV spectrum and shifted with the temperature in a decrease-increase-decrease manner; the so-called S-shaped behavior between 30-150 K. Remarkably, the shift continued with an increase in energy (blue shift) and finally saturated for a temperature above 150 K. The first variation below 150 K was explained by the composition fluctuation of In atom in the InGaN MQW layer. In contrast, the second significant shift in peak energy was caused to the localization effect, around 60 meV. The degree of localized (σ) value agreed with the activation energy of thermal quenching of PL intensity. A strong localization effect was also attributed to the sub-bandgap trap level in the quantum well and originated negative capacitance in admittance spectroscopy measurement. DOI:10.1016/j.jlumin.2023.119749
Ekip : Orhan Özdemir, Hanife Baş, Neslihan Ayarcı Kuruoğlu, Kutsal Bozkurt, Mustafa Aydın, Fahrettin Sarcan, Ayşe Erol, Bandar Alshehri, Karim Dogheche, Elhadj Dogheche - Adı : A novel NiO-based p-i-n ultraviolet photodiode
Açıklama : In this study, the electrical and optical properties of a novel NiO-based homojunction p-i-n photodiode are reported. The p-i-n diode structure consists of Mg-doped, intrinsic and Cu-doped NiO from the top to the bottom layers, respectively. The photodiode structure was grown on a 0.7 % Nb-doped SrTiO3 (001) substrate using molecular beam epitaxy. The homojunction p-type NiO:Mg/i-NiO/n-type NiO:Cu exhibits diode characteristics. The ideality factor and barrier height of the diode are found to be 1.26 and 0.66 eV, respectively. The photoconductive properties of the photodiode were investigated by operating the diode under reverse bias, and spectral excitation of a Xe lamp. The responsivity of the photodiode is determined to be 295 mA/W at 3.9 eV. A constant photoresponse of the p-i-n photodiode between 3.75 eV and 6 eV with a responsivity of 250 mA/W is observed. DOI:10.1016/j.jallcom.2022.167806
Ekip : Fahrettin Sarcan, Umit Doğan, Ahmad Althumali, Hari B. Vasili b, Leonardo Lari, Adam Kerrigan, Furkan Kuruoğlu, Vlado K. Lazarov, Ayşe Erol - Adı : Influence of the Core Pillar Height on the Bandgap Characteristics of Piezoelectric Phononic Crystals with Ring-Shaped Grooves
Açıklama : Dispersion profiles and surface acoustic wave attenuation characteristics of ring-shaped phononic crystals are investigated as a function of the core pillar height. Finite element method simulations are carried out for both band analyses and transmission spectra calculations. The results reveal that the increase at the core pillar height leads to a decrement in the local resonance band gap frequencies and the corresponding transmission peaks. The obtained dispersion profiles show that the phononic crystal bandgap also expands from 6 MHz to 11 MHz while the pillar height increases from 5 m to 7 m. Similar characteristics are also seen in the transmission spectra for the varying core pillar heights of the ring-shaped periodic grooves. In addition, surface acoustic wave attenuation competency depends on the core pillar height. The resonant frequency of the phononic crystals can be tuned by adjusting the core pillar height. DOI: 10.17776/csj.1104315
Ekip : Furkan KURUOĞLU - Adı : Integer quantum Hall effect measurement analysis in Ga0.68In0.32N0.017As/GaAs quantum wells with various annealing time
Açıklama : The integer quantum Hall Effect (QHE) and magnetoresistance measurements are carried out at temperature range 1.8 K and 40 K under a magnetic field up to 11 T to investigate the influence of the thermal annealing process and thermal annealing time on the transport parameters of as-grown and annealed n-type Ga0.68In0.32N0.017As0.983/GaAs quantum well (QW) structures. The electron effective mass, two-dimensional (2D) carrier density, quantum lifetime, and Fermi level are obtained by analyzing both oscillatory parts of magnetoresistance measurements (Shubnikov de Haas oscillations) and QHE oscillations. The compatibility of two different methods with each other is discussed, and the dependence of physical parameters obtained from both methods on annealing time was discussed. Our results reveal that the thermal annealing process and annealing duration time affect 2D carrier density, electron effective mass, quantum lifetime, transport lifetime, and Fermi level. The increase in annealing time showed that ratios caused the shift from long-range scattering to short-range scattering in the low-temperature region. DOI:10.1016/j.physb.2021.413305
Ekip : Sukru Ardali, Engin Tiras, Ayse Erol - Adı : A novel hot carrier-induced blue light-emitting device
Açıklama : In this work, an InGaN/GaN multiple quantum well based Top-Hat Hot-Electron Light Emission and Lasing in a Semiconductor Heterostructure (Top-Hat HELLISH) is investigated. A heterojunction structure is designed based on an active InGaN quantum well placed in the n-type GaN region sandwiched by the n- and p-type GaN layers. The four quantum well structure of an InGaN/GaN heterojunction where the Indium ratio is 0.16 has been grown via Metal-Organic Chemical Vapor Deposition. In order to create an anisotropic potential distribution of the heterojunction, it is aimed to fabricate TH-HELLISH-GaN device in Top-Hat HELLISH (THH) geometry for four contacts with separate n- and p-channels. High-speed I-V measurements of the device reveal an Ohmic characteristic at both polarities of the applied voltage. Integrated EL measurements reveal the threshold of the applied electric field at around 0.25 kV/cm. The emission wavelength of the device is around 440 ± 1 nm at room temperature. DOI:10.1016/j.jallcom.2021.160511
Ekip : S. Mutlu, A. Erol, E. Arslan, E. Ozbay, S.B. Lisesivdin , E. Tiras - Adı : A practical and cost-effective method to make permanently bonded acoustofluidic chips reconfigurable
Açıklama : Acoustofluidic devices that save space and cost are promising for in-situ diagnosis and also the prognosis of many diseases including bacterial infections and cancer. Acoustofluidic devices owe their merit to the combined use of two functional materials, usually lithium niobate and polydimethylsiloxane. While the permanent bonding between lithium niobate-based surface acoustic wave chips and polydimethylsiloxane-based microchannel gives a wide range of functionality, it inevitably limits such devices to single-purpose use where versatility is absent. Here, a bond-detach procedure was demonstrated as a practical and cost-efficient method that enables design modification either in a lithium niobate chip or microchannel. Hence, by simply replacing either constituent, modified acoustofluidic devices targeted for different microbody types or sizes can be realized. The proposed approach to detach permanently bonded acoustofluidic devices via oxygen plasma treatment is based on immersing the devices in 0.1 M potassium hydroxide solution for two hours. It is clearly seen that the bond-detach procedure can be applied at least three times without any significant deterioration in either piezoelectric surface or microfluidic channel in terms of mechanical, optical and chemical properties. Moreover, no significant shift or attention was observed in the transmission spectra of interdigital transducers pairs after the application of the procedure three times. The proposed approach can help durability and reusability of acoustofluidic devices against factors such as clogging, and mechanical or chemical degradation. DOI: 10.1007/s10404-022-02579-3
Ekip : Furkan KURUOĞLU - Adı : Preventive effects of matrix-metalloproteinase inhibitors on dental erosion
Açıklama : The purpose of this study was to investigate the effects of Chlorhexidine (CHX) and Epigallocatechin-3-gallate (EGCG) on dental erosion. Forty-four non-carious, recently extracted human third molars were used. The 44 dental crown slabs were randomly divided into 4 groups as follows: Group 1: 1.100 ppm Sodium Fluoride (NaF), Group 2: 0.61% EGCG, Group 3: 12% CHX, Group 4: 0.2 % CHX. Samples individually immersed in 30 mL of Coke® for 5 days, 4 times, 1 minute a day for erosive demineralization. The samples were immersed in 1.100 Sodium Fluoride (NaF), 0.61% EGCG, 12% CHX, 0.2% CHX for 4 times, 1 minute, each day for remineralization. The changes in the dental surface were evaluated by using a stylus profiler with surface roughness (Ra values). Topographic characteristics were assessed by Scanning Electron Microscope (SEM). Mann-Whitney U, Kruskal Wallis, and Wilcoxon Signed Ranks tests were used for statistical analyses. Significant decrease was observed in the remineralization measurement of Ra values in the EGCG group when compared with the demineralization values (p<0.05). SEM evaluation revealed that remineralization images of EGCG were observed more regularly than the other materials. With regard to topography; EGCG was found as successful as CHX and NAF in terms of turning demineralized areas into remineralized areas. https://www.fluorideresearch.online/epub/files/154.pdf
Ekip : Mine Koruyucu, Ceren İlisulu, Fahrettin Sarcan, Furkan Kuruoglu, Ayşe Erol, Figen Seymen - Adı : A quantitative analysis of electronic transport in n- and p-type modulation-doped GaAsBi/AlGaAs quantum well structures
Açıklama : Electronic transport properties of as-grown and thermally annealed n- and p-type modulation-doped GaAsBi/AlGaAs quantum well (QW) structures were investigated. Hall mobility of as-grown, n- and p-type modulation doped QW structures are found from raw experimental data as ∼1414 and 95 cm2 Vs−1 at room temperature. A comparison between reported two-dimensional (2D) electron density determined from the analyses of Shubnikov de Haas oscillations and the 2D Hall electron density indicates a presence of parallel conduction in barrier layer (AlGaAs) and QW layer (GaAsBi) in n-type samples, therefore a parallel channel conduction theory is used to separate the electron mobility in the QW and the barrier layers in n-type modulation doped GaAsBi/AlGaAs QW structure. The extracted electron mobility of the as-grown n-type GaAsBi/AlGaAs QW sample is determined as ∼5975 cm2 Vs−1 at 4.2 K, which is closer to the electron mobility in GaAs. It is found that thermal annealing at lower temperature than growth temperature increases electron mobility of 2D electron gas, while annealing at higher temperature than growth temperature decreases electron mobility. The temperature dependence of the extracted electron mobility using parallel conduction approximation is analytically calculated by considering possible scattering mechanisms. Analysis of temperature-dependent electron mobility shows that the dominant scattering mechanisms are interface roughness (IFR), acoustic, and alloy-potential scatterings at low and intermediate temperature range, and IFR and optical phonon scattering at the high-temperature range in n-type modulation doped GaAsBi/AlGaAs QW structures. DOI:10.1088/1361-6641/ac2af0
Ekip : Omer Donmez, Ayse Erol, Çağlar Çetinkaya, Erman Çokduygulular, Mustafa Aydın, Saffettin Yıldırım, Janne Puustinen, Joonas Hilska and Mircea Guina - Adı : Temperature-dependent sandwich and in-plane optical characterization of ternary chalcogenide TlSbS2
Açıklama : We have studied the temperature-dependent optical absorption and emission mechanisms of ternary chalcogenide TlSbS2 by carrying out sandwich and planar photoconductivity, and photoluminescence measurements in the temperature range 30 K to 300 K. Two main transitions were observed in the room temperature photoconductivity spectrum at energies of 1.74 and 1.84 eV, which are attributed to a native acceptor–donor transition and a band-to-band transition, respectively. A spectral anisotropy near the bandgap energy of TlSbS2 is observed between the sandwich and in-plane photoconductivity spectrum. In the photoluminescence spectrum, we observed deep-level broadband emission which is correlated with the native defect-related transition-based free-to-bound recombination between 30 K and 70 K. The Debye temperature of TlSbS2 was found to be 280 K, and the thermal expansion coefficient was determined as from the analyses of its temperature-dependent photoconductivity spectra. DOI:10.1016/j.mseb.2021.115322
Ekip : Fahrettin Sarcan, Mustafa Aydin, Furkan Kuruoğlu, Omer Donmez, Saffettin Yildirim, Ayşe Erol - Adı : Improved performance of CdS powder-based hybrid solar cells through surface modification
Açıklama : The effects of surface modification of CdS through organic Eosin-Y, indoline D205, and Ru-based complex N719 and N3 dyes on CdS-based hybrid solar cells were studied. Chemical bath deposition (CBD) and doctor blade methods were in turn employed to fabricate the CdS specimens on Indium-Tin Oxide (ITO) covered glass substrates. P3HT material with and without dye coatings was covered through a spin-coater on the surface of CdS specimens. Ag paste was then deposited on the surface of P3HT to obtain hybrid solar cells. Structural analysis indicated that CdS powders showed a cubic growth with the preferred orientation of (111). Morphological analysis demonstrated that CdS powders exhibited hierarchical morphology and the morphology turned to granular structure with some porosity upon deposition of both N3 dye and P3HT layers. Absorption plots indicated that Eosin-Y dye loading led to a rise in the absorbance values of CdS specimens. After dye loading, photoluminescence data of CdS-based heterostructure illustrated a decrement in the luminescence intensity, implying that effective exciton dissociation was obtained. Current density-voltage (J-V) characteristics of the hybrid solar cells depicted that the best overall efficiency was observed for Eosin-Y-modified cell as 0.135%. This proved that surface modification by Eosin-Y dye led to a better interfacial contact between CdS and P3HT bilayer due to the enhancement in the charge separation. DOI:10.17714/gumusfenbil.893925
Ekip : Salih YILMAZ,Ahmet ÜNVERDİ, Murat TOMAKİN, İsmail POLAT, Emin BACAKSIZ - Adı : Determination of band tail widths in MOCVD grown InGaN single layer within GaN based p-i-n LED structure through photo-induced measurements
Açıklama : Within a p-i-n LED structure, energy band gaps of MOCVD grown %10 In content InGaN and GaN layers were obtained through traditional UV–Visible transmission-absorption measurements and utilizing surface photovoltage (SPV) and spectral photoconductivity (SPC) measurements. Moreover, all applied techniques determined that the total band offset between InGaN and GaN layers were around 0.3–0.4 eV. Furthermore, the temperature dependence of band gaps of each InGaN and GaN layer was analyzed through a modified Varshni relation where both Varshni coefficients and band tail energy width were explored. Band tails in a modified Varshni relation, SPV and SPC measurements were in agreement with each other and originated Franz-Keldysh Effect attributed to the presence of photon assisted tunneling. DOI: 10.1016/j.jlumin.2022.119543
Ekip : Orhan Özdemir, Kutsal Bozkurt, Neslihan Ayarcı Kuruoğlu,Hanife Baş ,Fahrettin Sarcan, Ayşe Erol , Bandar Alshehri , Karim Dogheche , Elhadj Dogheche
| Adı | Açıklama | Ekip |
|---|---|---|
| Ultraviyole Işınım Algılamaya Yönelik "Solar Blind" Yarıiletken Sensör Geliştirilmesi | Bu proje, Nero Savunma Sanayi A.Ş. ile ortaklaşa yürütülen bir projedir. Alevin DUV (Derin Ultraviyole) karakteristik emisyonunu algılayan bir sensör üretmeyi hedefliyoruz. Prototip sensör, Prof. Dr. Ayşe Erol ve Doç. Dr. Fahrettin Sarcan tarafından tasarlandı, üretildi ve test edildi. Prototip, Teknoloji Hazırlık Seviyesi 3 (THS 3) düzeyindedir. | Nero Endüstri (Proje Partneri), Prof. Dr. Ayşe Erol (Yürütücü), Doç. Dr. Fahrettin Sarcan (Yürütücü), Ümit Doğan (Araştırmacı) |
| Adı | Açıklama | Ekip |
|---|---|---|
| OPTİK OLARAK ÖLÇÜM YAPAN BİR MANYETİK ALAN ÖLÇÜM CİHAZI | Ömer DÖNMEZ, Ayşe EROL | |
| VÜCUT SICAKLIĞI AYARLAMA ÜNİTESİ | Ayşe EROL | |
| Dalgaboyu Seçiciliği Yüksek İç Kazançlı Rezonans Kaviteli Fotodedektör | Fahrettin SARCAN , Ayşe EROL |
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| Proje (TÜBİTAK) | 1.3 μm Dalga Boyunda Çalışan Kazançlı GaInNAs Tabanlı Rezonans Kaviteli Geliştirilmiş Fotodetektörler | Bu proje, belirli bir dalga boyunda optik bilgi alırken diğerlerini reddeden yeni fotodetektörlerin geliştirilmesiyle ilgilidir. Bu tür dedektörlerin temelini oluşturabilecek birçok yarı iletken malzeme vardır ve her biri farklı bir dalga boyuna duyarlıdır. Bu projede GaInNAs/GaAs yapısını kullanacağız. | Ayşe Erol (Yürütücü), Mehmet Çetin Arıkan (Araştırmacı), Naci Balkan (Araştırmacı), Fahrettin Sarcan (Öğrenci), Furkan Kuruoğlu (Öğrenci) |
| Proje (TÜBİTAK) | Seyreltik Bizmut Modülasyonu Katkılı GaAsBi/GaAs Kuantum Kuyusu Yapılarında Bizmut Konsantrasyonunun Elektronik Transport Özelliklerine Etkisi | Bu projede, Biszut'un n- ve p- modülasyonlu katkılanmış kuantum kuyu yapıları üzerindeki optik ve elektronik transport üzerindeki etkileri, çeşitli bizmut konsantrasyonlarıyla incelenecektir. Kullanılacak örnekler, proje ekibi tarafından tasarlandı ve bunlar Tampere Teknik Üniversitesi, Finlandiya'da büyütüldü. Optik özellikler, Fotolüminesans ve Foto-modüle Edilmiş Yansıma teknikleri kullanılarak incelenirken, elektronik taşıma mekanizmalarını belirlemek için Hall Etkisi ve manyetotransport ölçümleri gerçekleştirilecektir. Ayrıca, elektron ve boşlukların satürasyon hızlarını belirlemek ve NDR etkisinin varlığında yüksek hızlı I-V ölçümleri yapılacaktır. | Prof Dr. Ömer Dönmez(Yürütücü), Prof. Dr. Ayşe Erol (Araştırmacı), Saffettin Yıldırım (Araştırmacı), Ferhat Nutku (Araşırmacı), Mehmet Çetin Arıkan (Danışman) |
| Proje (TÜBİTAK) | InGaAs Gunn Diyodu Tabanlı Işık Yayan Aygıtlar | Projede, Gunn diyotlarının aktif tabakası, dalga boyunu yaklaşık 1550 nm civarında genişletmek amacıyla InGaAs yarıiletkeninden oluşmaktadır. Gunn diyot, sadece bir tür katkılı epilayerın aktif tabaka olarak kullanıldığı bir yapıya sahiptir ve çalışma koşulları, ileri yönlü besleme gerektiren p-n diyot laser yapısından farklıdır. Gunn laseri, her iki voltaj polaritesi altında çalışırken, bir p-n diyot laseri için ileri yönde beslemeye ihtiyaç duyulur. Projede, hem dalga kılavuzlu hem de dalga kılavuzu olmayan Gunn diyotları incelenmektedir. | Ayşe Erol (Yürütücü), Selman Mutlu (Araştırmacı), İlkay Demir (Araştırmacı), İzel Pertikel (Öğrenci), Göksenin Kalyon (Öğrenci), Saleh Mohammad AMINI (Öğrenci) |
| Proje (TÜBİTAK) | Dalgaboyu Ayarlanabilir 2B TMDC/MEMS Hibrit Işık Yayan Diyot | Bu araştırma projesinde, iki boyutlu (2B) formlarıyla sıra dışı özelliklere sahip olan Geçiş Metali Dikalkojenit (Transition Metal Dichalcogenides, TMDC) ailesinden olan MoTe2 yarıiletkeni ve mikro elektromekanik sistem (MEMS) tabanlı ışıma dalgaboyu ayarlanabilen p-n eklem 2B MoTe2/MEMS hibrit ışık yayan diyot (Light Emitting Diode, LED) üretilmesi amaçlanmaktadır. | Doç. Dr. Fahrettin Sarcan (Yürütücü), Dr. Yue Wang (Danışman), Prof. Dr. Ayşe Erol (Araştırmacı) |
| Proje (TÜBİTAK) | Ultraviyole Işınım Algılamaya Yönelik "Solar Blind" Yarıiletken Sensör Geliştirilmesi | Bu proje, Nero Savunma Sanayi A.Ş. ile ortaklaşa yürütülen bir projedir. Alevin DUV (Derin Ultraviyole) karakteristik emisyonunu algılayan bir sensör üretmeyi hedefliyoruz. Prototip sensör, Prof. Dr. Ayşe Erol ve Doç. Dr. Fahrettin Sarcan tarafından tasarlandı, üretildi ve test edildi. Prototip, Teknoloji Hazırlık Seviyesi 3 (THS 3) düzeyindedir. | Nero Endüstri (Proje Partneri), Prof. Dr. Ayşe Erol (Yürütücü), Doç. Dr. Fahrettin Sarcan (Yürütücü), Ümit Doğan (Araştırmacı) |
| Proje (Kalkınma Bakanlığı) | İleri Litografik Yöntemler Laboratuvarı | Kalkınma Bakanlığı Proje No: 2010K121050 | Prof. Dr. Çetin Arıkan (Yürütücü) Prof. Dr. Ayşe Erol (Yardımcı Araştırmacı) |
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