MODELING OF ATMOSPHERE SENSITIVE HETEROJUNCTIONS FOR DEVICE APPLICATIONS

摘要

Simple and inexpensive methods of detecting pollutants in ambients are needed for maintenance of safe environment in modern industries. Chemical sensors based on catalytic combustion and using solid state electrolytes and semiconducting oxides etc. are being developed for this purpose. Sensors based on semiconducting oxide utilise the resistivity change in oxide semiconductor material when they are exposed to pollutants. Heterojunctions are known to be atmosphere sensitive, and they are also incorporated in there sensors to increase their sensitivities. Electrical properties of heterjunctions such as CuO-SnO_2, CuO-ZnO, NiO-ZnO and NiO-SnO_2, and their dependence on composition of ambient gas phase have been studied experimentally, mainly by carrying out I-V and C-V characteristics of junctions to achieved between individual pellets by spring loading them. Band energy diagrams corresponding to these junctions would be needed to understand their properties and these are not available. In the paper, synthesised band energy diagrams of these heterojunctions are purposed based on reported experimental data.