High-Speed Solar-Blind AlGaN Schottky Photodiodes
- PDF / 133,096 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 32 Downloads / 218 Views
C5.8.1
High-Speed Solar-Blind AlGaN Schottky Photodiodes Necmi Biyikli1, Ibrahim Kimukin2, Tolga Kartaloglu1, Orhan Aytür1, and Ekmel Ozbay2 1 Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara, 06800 TURKEY 2 Department of Physics, Bilkent University, Bilkent, Ankara 06800 TURKEY ABSTRACT We report high-speed solar-blind AlGaN-based Schottky photodiodes. AlGaN/GaN heterostructure device layers were grown on sapphire substrate. The devices were fabricated on AlGaN/GaN heterostructuresusing a microwave compatible fabrication process. Schottky photodiodes with Au and indium-tin-oxide (ITO) Schottky contacts were fabricated. Currentvoltage, spectral responsivity, and high-speed measurements were performed. Both Schottky samples exhibited very low sub-pA dark currents at high reverse bias. A bias dependent spectral responsivity was observed with a peak responsivity of 89 mA/W at 267 nm, and 44 mA/W at 263 nm for Au and ITO-Schottky devices respectively. Time-based high-frequency measurements at 267 nm resulted in pulse responses with rise times and pulse-widths as short as 13 ps and 74 ps respectively. The fastest solar-blind detector had a record 3-dB bandwidth of 1.10 GHz. INTRODUCTION With its wide bandgap and intrinsic visible-blind absorption spectrum, AlxGa1-xN ternary alloy is the most promising material system for high-performance photodetectors operating in the ultraviolet (UV) spectrum [1]. Their cut-off wavelength (λc) can be tuned from 365 nm to 200 nm, which covers the solar-blind spectrum (λ
Data Loading...
