High-Sensitivity Focus-Induced Photoresponse in Amorphous Silicon Photodiodes for Enhanced Three-Dimensional Imaging Sensors

In this work, we report on the bias-tunable and highly sensitive irradiance-dependent focus-induced photoresponse (FIP) in amorphous silicon p-i-n diodes for enhanced three-dimensional imaging applications. We identify a nonlinear current breakdown at irradiance down to at least 0.6 mu W/mm(2) due to defect-induced electrical field screening, surpassing state-of-the-art device sensitivities by at least a factor of 16 in the visible range. We further demonstrate the tunability of FIP by systematic device and field engineering to enable both precise and long-range high-resolution distance measurements in just one device architecture. We evaluate distance measurements up to at least 15 m and achieve a depth resolution of 2.1 mm at 3.3 m. The reproducible low-temperature (300 degrees C or lower) plasma-enhanced chemical vapor-deposition technology enables systematic tailoring of the FIP for three-dimensional imaging applications and allows for back-end sensor integration on top of silicon or flexible electronics with fill factors up to 100%.