Carrier Transport and Photogeneration in Amorphous Silicon / Crystalline Silicon Heterojunctions with i/n and p/n Interfaces

Abstract

ABSTRACTAmorphous hydrogenated silicon films deposited by Plasma Enhanced Chemical Vapour Deposition (PE-CVD) using standard rf-glow discharge at 13.56 MHz were used to produce amorphous silicon heterostructures. Junction properties were studied from current-voltage (IV), capacitance-voltage (C-V) and spectral response measurements. The photosensitivity of these structures was investigated for different amorphous film thicknesses and different applied bias voltages. It was shown that the output device characteristics could be improved by plasma hydrogen treatment before the deposition of the amorphous layer. The results show that ITO/a-Si:H/c-Si structures present high internal gain in the visible infra-red region and high collection efficiency in the blue range. They can be used as visible/near-IR photodiodes or for current amplifications proposes.