III-Nitride Visible- and Solar-Blind Avalanche Photodiodes; Final technical rept. Apr-Nov 2007

摘要

There is a need for single photon detectors for a variety of scientific, military, and civilian applications. Compared to photomultiplier tubes or superconducting single photon detectors, the use of Geiger-mode avalanche photodiodes (APDs) presents advantages such as lower operation voltages, reduced sizes, and reduced need for cooling, which may enable the fabrication of more compact, lower power, and all-solid-state APD/CMOS integrated arrays. APDs based on wide-band-gap semiconductors are of special interest when there is a need for reliable ultraviolet detection with single photon counting capabilities. The tunable response of AlGaN detectors allows for solar- to visible-blind performances within the same material system, without the need of filters. We report on the growth, fabrication, and characterization of back-illuminated GaN APDs on thick AlN templates. Comparison of the performance of these same devices under front and back illumination allows us to reach a better understanding of carrier multiplication in this material and to determine experimentally both electron and hole ionization coefficients. Devices of various mesa sizes were fabricated and the effects of increased area on device performance were studied. Finally, devices were characterized in Geiger mode to evaluate their capabilities for single-photon detection.