Now showing items 1-20 of 21

    • 100-GHz resonant cavity enhanced Schottky photodiodes 

      Onat, B. M.; Gökkavas, M.; Özbay, Ekmel; Ata, E. P.; Towe, E.; Ünlü, M. S. (Institute of Electrical and Electronics Engineers, 1998)
      Resonant cavity enhanced (RCE) photodiodes are promising candidates for applications in optical communications and interconnects where ultrafast high-efficiency detection is desirable. We have designed and fabricated RCE ...
    • 45 GHz bandwidth-efficiency resonant cavity enhanced ITO-Schottky photodiodes 

      Bıyıklı, Necmi; Kimukin, İbrahim; Aytür, Orhan; Özbay, Ekmel; Gökkavas, M.; Ünlü, M. S. (OSA, 2001)
      We demonstrated high-performance resonant cavity enhanced ITO-Schottky photodiodes. We achieved a peak efficiency of 75% around 820 nm with a 3-dB bandwidth of 60 GHz resulting in a bandwidth-efficiency product of 45 GHz.
    • 45-GHz bandwidth-efficiency resonant-cavity-enhanced ITO-Schottky photodiodes 

      Bıyıklı, Necmi; Kimukin, I.; Aytür, O.; Gökkavas, M.; Ünlü, M. S.; Özbay, Ekmel (IEEE, 2001)
      High-speed Schottky photodiodes suffer from low efficiency mainly due to the thin absorption layers and the semitransparent Schottky-contact metals. We have designed, fabricated and characterized high-speed and high-efficiency ...
    • AlGaN-based high-performance metal-semiconductor-metal photodetectors 

      Gökkavas, M.; Butun, S.; Tur, T.; Bıyıklı, Necmi; Özbay, Ekmel (Elsevier BV, 2007-10)
      Design, structure growth, fabrication, and characterization of high performance AlGaN-based metal–semiconductor–metal (MSM) photodetectors (PD) are reported. By incorporating AlN nucleation and buffer layers, the leakage ...
    • Deep-ultraviolet Al0.75Ga0.25N photodiodes with low cutoff wavelength 

      Bütün, S.; Tut, T.; Bütün, B.; Gökkavas, M.; Yu, H.; Özbay, Ekmel (AIP Publishing LLC, 2006-03-21)
      Deep ultraviolet Al0.75Ga0.25N metal-semiconductor-metal photodetectors with high Al concentration have been demonstrated. A metal-organic chemical vapor deposition grown high quality Al0.75Ga0.25N layer was used as a ...
    • Design and optimization of high-speed resonant cavity enhanced Schottky photodiodes 

      Gökkavas, M.; Onat, B. M.; Özbay, Ekmel; Ata, E. P.; Xu, J.; Towe, E.; Ünlü, M. S. (Institute of Electrical and Electronics Engineers, 1999-02)
      Resonant cavity enhanced (RCE) photodiodes (PD's) are promising candidates for applications in optical communications and interconnects where high-speed high-efficiency photodetection is desirable. In RCE structures, the ...
    • Dual-color ultraviolet metal-semiconductor-metal AlGaN photodetectors 

      Gökkavas, M.; Bütün, S.; Yu, H.; Tut, T.; Bütün, B.; Özbay, Ekmel (AIP Publishing LLC, 2006)
      Backilluminated ultraviolet metal-semiconductor-metal photodetectors with different spectral responsivity bands were demonstrated on a single Alx Ga1-x N heterostructure. This was accomplished by the incorporation of an ...
    • Experimental demonstration of a left-handed metamaterial operating at 100 GHz 

      Gökkavas, M.; Güven, K.; Bulu, I.; Aydın, K.; Penciu, R. S.; Kafesaki, M.; Soukoulis, C. M.; Özbay, Ekmel (American Physical Society, 2006)
      The existence of a left-handed (LH) transmission band in a bulk composite metamaterial (CMM) around 100 GHz is demonstrated experimentally. The CMM consists of stacked planar glass layers on which periodic patterns of ...
    • Experimental evaluation of impact ionization coefficients in Al xGa1-xN based avalanche photodiodes 

      Tut, T.; Gökkavas, M.; Bütün, B.; Bütün, S.; Ülker, E.; Özbay, Ekmel (AIP Publishing LLC, 2006)
      The authors report on the metal-organic chemical vapor deposition growth, fabrication, and characterization of high performance solar-blind avalanche photodetectors and the experimental evaluation of the impact ionization ...
    • Fabrication of high-speed resonant cavity enhanced schottky photodiodes 

      Özbay, Ekmel; Islam, M. S.; Onat, B.; Gökkavas, M.; Aytür, O.; Tuttle, G.; Towe, E.; Henderson, R. H.; Ünlü, M. S. (Institute of Electrical and Electronics Engineers, 1997-05)
      We report the fabrication and testing of a GaAs-based high-speed resonant cavity enhanced (RCE) Schottky photodiode. The top-illuminated RCE detector is constructed by integrating a Schottky contact, a thin absorption ...
    • High bandwidth-efficiency resonant cavity enhanced Schottky photodiodes for 800-850 nm wavelength operation 

      Ünlü, M. S.; Gökkavas, M.; Onat, B. M.; Ata, E.; Özbay, Ekmel; Mirin, R. P.; Knopp, K. J.; Bertness, K. A.; Christensen, D. H. (A I P Publishing LLC, 1998-05-25)
      High-speed resonant cavity enhanced Schottky photodiodes operating in 800-850 nm wavelength region are demonstrated. The devices are fabricated in the AlGaAs/GaAs material system. The Schottky contact is a semitransparent ...
    • High-speed >90% quantum-efficiency p-i-n photodiodes with a resonance wavelength adjustable in the 795-835 nm range 

      Özbay, Ekmel; Kimukin, İ.; Bıyıklı, Necmi; Aytür, O.; Gökkavas, M.; Ulu, G.; Ünlü, M. S.; Mirin, R. P.; Bertness, K. A.; Christensen, D. H. (A I P Publishing LLC, 1999-02-22)
      We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p-i-n photodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we ...
    • High-speed high-efficiency large-area resonant cavity enhanced p-i-n photodiodes for multimode fiber communications 

      Gökkavas, M.; Dosunmu, O.; Ünlü, M. S.; Ulu, G.; Mirin, R. P.; Christensen, D. H.; Özbay, Ekmel (IEEE, 2001)
      In this letter, we report AlGaAs–GaAs p-i-n photodiodes with a 3-dB bandwidth in excess of 10 GHz for devices as large as 60- m diameter. Resonant cavity enhanced photodetection is employed to improve quantum efficiency, ...
    • High-speed high-efficiency resonant cavity enhanced photodiodes 

      Özbay, Ekmel; Kimukin, I.; Bıyıklı, N.; Aytür, O.; Gökkavas, M.; Ulu, G.; Ünlü, M. S.; Mirin, R. P.; Bertness, K. A.; Christensen, D. H.; Towe, E.; Tuttle, G. (Society of Photo-Optical Instrumentation Engineers, Bellingham, WA, United States, 1999)
      In this paper, we review our research efforts on RCE high-speed high-efficiency p-i-n and Schottky photodiodes. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs based RCE ...
    • High-speed resonant-cavity-enhanced Schottky photodiodes 

      Ata, Erhan P.; Bıyıklı, Necmi; Demirel, Ekrem; Özbay, Ekmel; Gökkavas, M.; Onat, B.; Ünlü, M. S.; Tuttle, G. (IEEE, 1998)
      The top-illuminated Schottky photodiodes were fabricated by a microwave-compatible monolithic microfabrication process. Fabrication started with formation of ohmic contacts to n+ layers. Mesa isolation was followed by a ...
    • High-speed widely-tunable >90% quantum-efficiency resonant cavity enhanced p-i-n photodiodes 

      Bıyıklı, Necmi; Kimukin, İbrahim; Aytür, Orhan; Gökkavas, M.; Ulu, G.; Mirin, R.; Christensen, D. H.; Ünlü, M. S.; Özbay, Ekmel (IEEE, 1998)
      Widely-tunable high-speed resonant cavity enhanced p-i-n photodiodes were designed, fabricated and tested for operation around 820 nm. The structure was grown by solid-source MBE on GaAs substrates and features high-reflectivity ...
    • Improved selectivity from a wavelength addressable device for wireless stimulation of neural tissue 

      Seymour, E. Ç.; Freedman, D. S.; Gökkavas, M.; Özbay, Ekmel; Sahin, M.; Ünlü, M. S. (Frontiers Research Foundation, 2014)
      Electrical neural stimulation with micro electrodes is a promising technique for restoring lost functions in the central nervous system as a result of injury or disease. One of the problems related to current neural ...
    • Improving the efficiency enhancement of photonic crystal based InGaN solar cell by using a GaN Cap Layer 

      Gundogdu, T.F.; Gökkavas, M.; Özbay, Ekmel (Hindawi Publishing Corporation, 2014)
      We studied a high indium content (0.8) InGaN based solar cell design where the active InGaN layer is sandwiched between a GaN cap layer and a GaN spacer layer. The incorporation of the sacrificial cap layer allows for the ...
    • Integrated AlGaN quadruple-band ultraviolet photodetectors 

      Gökkavas, M.; Butun, S.; Caban, P.; Strupinski, W.; Özbay, Ekmel (IOP Publishing, 2012-04-27)
      Monolithically integrated quadruple back-illuminated ultraviolet metalsemiconductormetal photodetectors with four different spectral responsivity bands were demonstrated on each of two different Al xGa 1-xN heterostructures. ...
    • Low dark current metal-semiconductor-metal photodiodes based on semi-insulating GaN 

      Bütün, S.; Gökkavas, M.; Yu, H.; Özbay, Ekmel (AIP Publishing LLC, 2006)
      Metal-semiconductor-metal photodetectors on semi-insulating GaN templates were demonstrated and compared with photodetectors fabricated on regular GaN templates. Samples were grown on a metal organic chemical vapor deposition ...