Silicon nanocrystal-based photosensor on low-temperature polycrystalline-silicon panels

Abstract

A photodetector, comprising a layer of silicon nanocrystals that is sandwiched between two electrodes, is proposed and demonstrated in a photosensing application on low-temperature polysilicon panels. Laser annealing of silicon-rich oxide films can form nanocrystals that respond optimally to a certain absorption spectrum of a light source. These silicon nanocrystals are smaller than 10 nm in diameter, which size determines the effectiveness of their quantum confinement, and promote electron-hole pair generation in the photosensing region because of their direct band gap. Besides obtaining a photosensitivity that is comparable to that of a p-i-n diode, which is currently used in low-temperature polysilicon technology, the sensor maximizes the photosensing area of a pixel by its stacked structure. © 2007 American Institute of Physics.