<title>Megahertz bandwidth AlxGa1-xN/GaN-based p-i-n detectors</title>

Abstract

This paper discusses recent results of time response and spectral responsivity measurements made on AlGa1N/GaN-based p-i-n ultraviolet (UV) detectors with .03<x<O.12, where x is the aluminum concentration. A1Ga1N/GaN-based p-i-n detectors with response times (lie) as fast as 6 ns corresponding to greater than 26 MHz bandwidths are reported. Peak spectral responsivities of homojunction Al03Ga97N p-i-n UV detectors were found to be as high as 0.08 AIW at 343 nm while those of the Al.1Ga.9N/GaN p-i-ns were as high as 0. 15 A/W at 360 nm. Homojunction GaN and Al03Ga97N as well as p-Al.1Ga.9N/i-GaN/n-GaN (heretofore referred to as Al1Ga9N/GaN) structures were grown on sapphire substrates by reactive molecular beam epitaxy (MBE) and processed into UV detectors. These pi-n detectors were then characterized in terms of their time response and spectral responsivity. Attempts to measure the noiseof the A103Ga97N homojunction p-i-ns are also discussed.

Improved AlGaN p-i-n Photodetectors for Monitoring of Ultraviolet Radiation

“…The laser creates a high excitation intensity of photogenerated carriers, which saturates the trap states, and therefore, leads to faster response times [1], [26]. A longer decay time (1/e) of 29 ns was determined for GaN p-i-n photodiodes at higher excitation energy densities of 170 mJ/cm² by Smith et al [27].…”