Development of III-N UVAPDs for Ultraviolet Sensor Applications

摘要

High-resolution imaging in ultraviolet (UV) bands has many applications in defense and commercial systems. The shortest wavelength is desired for increased spatial resolution, which allows for small pixels and large formats. In past work, UV avalanche photodiodes (APDs) have been reported as discrete devices demonstrating gain. The next frontier is to develop UVAPD arrays with high gain to demonstrate highresolution imaging. We will discuss a model that can predict sensor performance in the UV band using APDs with various gain and other parameters for a desired UV band of interest. Signal-to-noise ratios (SNRs) can be modeled from illuminated targets at various distances with high resolution under standard atmospheric conditions in the UV band and the solar-blind region using detector arrays with unity gain and with high-gain APDs. We will present recent data on the GaN-based APDs for their gain, detector response, dark current noise, and 1/f noise. We will discuss various approaches and device designs that are being evaluated for developing APDs in wide-bandgap semiconductors. The paper will also discuss the state of the art in UVAPDs and the future directions for small unit cell size and gain in the APDs.