PHOTOCURRENT MULTIPLICATION IN A HYDROGENATED AMORPHOUS SILICON-BASED P-I-N JUNCTION WITH AN A-SIN-H LAYER

Photocurrent multiplication has been observed in a hydrogenated amorphous silicon-based p-i/a-SiN:H/i-n structure junction under a reverse biased condition. A systematic investigation on the photocurrent characteristics in this junction system has been carried out. It has been shown from the analysis of the results that multiplication arises from the interband tunneling injection of valence band "electron" through the a-SiN:H barrier layer. A device modeling on the basis of the experimental data permits us to design the device structure for achieving better performances. As a preliminary optimization of device structure, an external quantum efficiency exceeding 70 has been obtained under the operation voltage 30 V in the heterojunction photodiode having an a-SiN:H (thickness of 40 nm with optical energy gap 2.1 eV) at the p a-SiC:H/i a-Si:H interface. The proposed highly sensitive photomultiplier device might have a wide variety of application fields such as a solid-state imager for high-definition televisions, etc.