High-Sensitivity Visible-Blind AlGaN Photodiodes and Photodiode Arrays

Visible-blind UV cameras based on a 32 x 32 array of backside-illuminated GaN/AlGaN p-i-n photodiodes have been successfully demonstrated. The photodiode arrays were hybridized to silicon readout integrated circuits (ROICs) using In bump bonds. Output from the UV cameras were recorded at room temperature at frame rates of 30-240 Hz. These new visible-blind digital cameras are sensitive to radiation from 285-365 nm in the UV spectral region. new images from the first successful demonstration of ultraviolet (UV) digital cameras [8] based on an array of GaN/AlGaN heterostructure p-i-n photodiodes. These new (32 x 32 pixel) digital imagers are designed to sense radiation in the 285-365 nm wavelength band in the UV spectral region. Thus, the digital camera is visible-blind but is not solar-blind (250-280 nm). A discussion of photodiode properties is followed by a description of the experimental procedures employed to synthesize, process and study discrete photodiodes and photodiode arrays, and then by the experimental results obtained.