High bandwidth-efficiency solar-blind AlGaN Schottky photodiodes with low dark current


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Tut T. , Biyikli N., Kimukin I., Kartaloglu T., Aytur O., Unlu M., ...More

SOLID-STATE ELECTRONICS, vol.49, no.1, pp.117-122, 2005 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 49 Issue: 1
  • Publication Date: 2005
  • Doi Number: 10.1016/j.sse.2004.07.009
  • Title of Journal : SOLID-STATE ELECTRONICS
  • Page Numbers: pp.117-122
  • Keywords: AlGaN, Bandwidth-efficiency, Schottky photodiode, solar-blind, ZONE BAND-STRUCTURE, LOW-NOISE, ULTRAVIOLET PHOTODETECTORS, BARRIER PHOTODETECTORS, QUANTUM EFFICIENCY, WURTZITE PHASES, BULK ZINCBLENDE, GAN, ALXGA1-XN, TRANSPORT

Abstract

Al0.38Ga0.62N/GaN heterojunction solar-blind Schottky photodetectors with low dark current, high responsivity, and fast pulse response were demonstrated. A five-step microwave compatible fabrication process was utilized to fabricate the devices. The solar-blind detectors displayed extremely low dark current values: 30 pm diameter devices exhibited leakage current below 3 fA under reverse bias up to 12V. True solar-blind operation was ensured with a sharp cut-off around 266 nm. Peak responsivity of 147 mA/W was measured at 256 nm under 20 V reverse bias. A visible rejection more than 4 orders of magnitude was achieved. The thermally-limited detectivity of the devices was calculated as 1.8 x 10(13) cm Hz(12) W-1. Temporal pulse response measurements of the solar-blind detectors resulted in fast pulses with high 3-dB bandwidths. The best devices had 53 ps pulse-width and 4.1 GHz bandwidth. A bandwidth-efficiency product of 2.9 GHz was achieved with the AlGaN Schottky photodiodes. (C) 2004 Elsevier Ltd. All rights reserved.