ZnSe:Cr single crystals were obtained using diffusion-related doping with Cr. The diffusion of Cr was performed in an atmosphere of saturated Zn vapours, and the metallic Cr layer deposited on the crystal surface was used as the source. Lines corresponding to Cr absorption at 2.766, 2.717 and 2.406eV were observed in the optical-density spectrum at 77K. The highest Cr concentration in the crystals was determined from infra-red absorbance in the region of 0.72eV and was found to be equal to 8 x 1019 cm–3. It was shown that the diffusion profile of the Cr impurity could be determined by measuring the optical density of the crystals in the visible region of the spectrum. The diffusion coefficients D of Cr in ZnSe crystals at 1073 to 1273K were calculated. An analysis of the temperature dependence D(T) made it possible to determine the coefficients in the Arrhenius equation: D0 = 4.7 x 1010 cm2/s and E = 4.45eV.

Optical Absorption and Chromium Diffusion in ZnSe Single Crystals. Y.F.Vaksman, V.V.Pavlov, Y.A.Nitsuk, Y.N.Purtov, A.S.Nasibov, P.V.Shapkin: Semiconductors, 2005, 39[4], 377-80