We report the change of the defect structure in CdTe crystal surface layer after etching in 2% Br/Me solution. The resistance of the etched samples is lowered by more than one order of magnitude and their low-temperature PL excitonic lines are blurred. The explanation of these processes is the forming of the Cd depleted surface layer and increasing of the Cd vacancies concentration which are known to be shallow acceptors. As a consequence crystalline quality of this layer is worsened and surface leakage current increases considerably. We studied the possibility of improving the chemically treated sample properties and electrically active centers passivation by means of hydrogenization. CdTe:Cl single crystals grown by modified PVT are investigated. H diffusion into previously etched CdTe samples was performed by their exposure to H+ plasma created by glow discharge during 1 hour at 300 K and 0.025 Torr. Analysis of the temperature dependences of dark current and photocurrent testifies to partial restoring of the surface electrical properties for hydrogenized samples. It is seen from their resistivity increasing almost to those of cleaved samples and photosensitivity rise. We believe that these effects are caused by the hydrogen passivation of shallow acceptors centers; their ionization determines the dark conductivity at low temperatures. This assumption is confirmed by the intensity decreasing of PL bands in the edge region after hydrogenization. The improvement of surface quality is indicated by the change in the excitonic region of PL spectra. Bound exciton lines become much more prominent. Weak line of free exciton is also seen in hydrogenated as well as in cleaved samples spectra whereas it is not visible in the case of the chemically etched crystal.

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