Changes in the structure and stoichiometry of the p-CdTe surface as a result of etching have been studied by high-resolution x-ray photoelectron spectroscopy and the Rutherford backscattering method. Etching with bromine-methanol and bromine-butanol solutions is shown to enrich the surface with elementary tellurium (Te 0 ). The etching process is anisotropic, in particular, the extent of enrichment with Te 0 is not the same for A and B surfaces. Arguments are developed in favour of the heterophase nature of the etched surface. The presence of water in the etches leads to Te 0 oxidation in the course of etching. The mechanism of etching is discussed based on the data obtained.

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Photoelectric properties of MIS tunnel diodes produced on high-resistive p-type silicon wafers with thin aluminium nitride AlN insulator layer and Pd or Al metal gate electrodes were investigated. It was found that synthesized AlN films possess a fixed positive charge, which leads to the creation of near-surface inversion layer in silicon substrate. The ratio of the photocurrent to the dark current K = Iph / Idark (on / off ratio) was found to depend on the gate electrode material, illumination intensity and the applied reverse bias. For studied MIS structures K ratio varied from 10 4 to 10 5 and was two orders of magnitude higher than that for the control MS structure without the insulator layer. High on / off ratio of such MIS structures with AlN tunnelling insulator promotes their application as an effective photodetectors in optoelectronics.