Advanced Signal Processing of Photo-Excited Current Spectroscopy Based on Trap State Distribution for Photo-Sensor Applications

An improved measurement method using photocurrent spectroscopy of an amorphous indium-zinc-oxide (a-IZO) optical sensor is proposed to analytically calculate the density of state (DOS) distributions. In the signal conversion method for DOS calculation, the photocurrent spectrum was measured in the on-state and off-state regions and the current signal was converted. In addition, the trap state distribution in the band gap of a-IZO semiconductor was modeled by calculating the photo-current signal of the photo-sensor. The validity of the proposed photo-carrier spectroscopy was verified through comparison with photo-excited charge collection spectroscopy analysis. This photo-current spectroscopy-based measurement method greatly improved measurement duration and accuracy compared to threshold voltage-based analysis.