High-performance solar-blind photodectors based on AlxGa1-xN heterostructures


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Ozbay E., Biyikli N., Kimukin I., Kartaloglu T., Tut T. , Aytur O.

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, vol.10, no.4, pp.742-751, 2004 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 10 Issue: 4
  • Publication Date: 2004
  • Doi Number: 10.1109/jstqe.2004.831681
  • Title of Journal : IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
  • Page Numbers: pp.742-751
  • Keywords: AlGaN, detectivity, heterostructure, high speed, metal-semiconductor-metal (MSM), photodetector, p-i-n, Schottky, solar blind, ultraviolet, HIGH QUANTUM EFFICIENCY, LOW-NOISE, ALGAN, PHOTODETECTORS, GAN, PHOTODIODES, DETECTORS, SUPERLATTICES, NITRIDES, SILICON

Abstract

Design, fabrication, and characterization of high-performance AlxGa1-xN-based photodetectors for solar-blind applications are reported. AlxGa1-xN heterostructures were designed for Schottky, p-i-n, and metal-semiconductor-metal (MSM) photodiodes. The solar-blind photodiode samples were fabricated using a microwave compatible fabrication process. The resulting devices exhibited extremely low dark currents. Below 3 fA, leakage currents at 6-V reverse bias were measured on p-i-n samples. The excellent current-voltage (I-V) characteristics led to a detectivity performance of 4.9x10(14) cmHz(1/2)W(-1). The MSM devices exhibited photoconductive gain, while Schottky and p-i-n samples displayed 0.09 and 0.11 A/W peak responsivity values at 267 and 261 nm, respectively. A visible rejection of 2 x 10(4) was achieved with Schottky samples. High-speed measurements at 267 nm resulted in fast pulse responses with greater than gigahertz bandwidths. The fastest devices were MSM photodiodes with a maximum 3-dB bandwidth of 5.4 GHz.