No abstract

Surface compositions of single-crystal specimens of InSb have been investigated by XPS. A correlation between the degree of surface oxidation and the type of chemical etchant used has been found. This interpretation is based on chemical-shift data and argon-ion bombardment experiments, together with XPS results obtained on polycrystalline indium and antimony.

The influence of the deposition time and the ratio of hydroxide to lead ion concentration in the precipitation solution on the photoconductive properties of chemically deposited PbS layers was investigated. From measurements of time constant, noise and resistance, it could be shown how the deposition conditions control the number of trapping centres and carrier density. The trapping centres may be connected with excess lead atoms deposited in the PbS lattice under the conditions of pre­paration

In addition to the procedure of partial oxidation of lead sulfide layers in order to increase their photoconductivity it was found that reduction may have a similar effect.When used as additives to the conventional thiourea-plumbite solution, the compounds aminoiminomethanesulfinic acid (1), rongalite or sodium dithionite, which all may form sulfoxylate in aqueous solution, enhance the photoconductivity of the deposited layers.Addition of H2O2 or PbO2 has a similar, less pronounced effect, which may also be ascribed to the intermediate oxidation of thiourea to 1.

Two possible ways are reported of influencing the spectral response of PbS films prepared by chemical deposition. An increase in the ratio of hydroxyl to lead ions in the deposition solution causes a shift of the peak spectral response from 1.3 μ to 2.8 μ. The addition of a reducing agent (hydroxyl amine hydrochloride) also markedly influences the spectral response. The time constant, resistance and thickness of the films have been measured and an attempt is made to explain all the observations on the basis of a modified conduction model