Gas environment type and pressure influence on the semiconductor thin films electrical properties

摘要

The topic timeliness is due to the semiconductor films widespread use in optoelectronic systems and the atmospheric gases adsorption influence on the film semiconductor devices operability. The study subject is to set the space charge area sign of zinc and cadmium chalcogenide films in the hydrogen, carbon monoxide (II) environment and their mixture by electrical conductivity measurements. Thin semiconductor films complex studies have proved the gaseous environment form and its pressure impact on the chalcogenide films electrical properties. The gas environments adsorbed components on the film surface compared to the vacuum lead to negative charge in the space charge area (p-CdTe) and to positive charge when there is hydrogen adsorption (n-CdSe). When using film in the wet air its surface oxidation and aging lead to opposite change in its charging nature as compared with the vacuum environment. The energy interval width (ΔE0) when exposed to gaseous environments is increased for n-CdSe to 18% in carbon monoxide (II) atmosphere, and it increases to 30% in hydrogen atmosphere. For compounds p-CdTe the similar values are respectively 13 and 17%. A method for stabilizing n-CdSe surface electrical properties by hydrogen annealing at T = 673K followed with thermovacuuming.