Study Of PbTe Photovoltaic Detectors

Ⅳ-Ⅵgroup materials which are narrow gap semiconductors have been considered as ideal materials for the development of infrared photodetector due to their unique characteristics. In this work, the background of IV-VI material was introduced briefly and then the development of infrared detector and infrared imaging system was generally reviewed in the first chapter. After in-depth study of the principle of photovoltaic detector, a device model of photovoltaic mid-IR detector based on the In2O3/PbTe heterojunction was designed by taking the physical properties ofⅣ-Ⅵmaterial into account.PbTe thin films on CdZnTe(111) substrates were epitaxially grown by using the independent Molecular Beam Epitaxy Equipment. The physical properties of the thin films are characterized by a series of test, the results show that the thin films have high crystal quality. Prototype photovoltaic mid-IR detectors were fabricated by using In2O3 as transparent conductive thin films, ZnS thin films as insulated materials and metallic In thin films as the Ohmic contact electrodes. The response wavelength of the detectors covers from 1.5μm to 5.5μm at 77K, and the detectivity is higher than 2×1010cm·Hz1/2W-1. The peak detectivity calculated using R0A data, which is obtained byⅠ-Ⅴcharacteristics, reaches 4.35×1010cm·Hz1/2W-1 at 77K.Finally, my major work during my master of science was summarized, and the following work on PbTe photovoltaic detectors was prospected.