An experimental study has been made of the effect of Sb diffusion on the crystalline quality and surface composition of Pb1minus;xSnxTe single crystals (xape;0.13) used in fabricating homojunction diode lasers. Both ion backscatteringhyphen;channeling and Auger electron spectroscopy have been employed. It is found that the crystalline quality in the bulk improves on diffusion, due to a decrease in dislocation density associated with the diffusion temperature. In the nearhyphen;surface region the quality deteriorates, due to the production of defects which are probably small clusters associated with Sb. The most pronounced effect is a partial or total loss of Te (and probably Sn) from the native oxide, accompanied by other changes in the oxide composition. A long term growth of a very thick oxide also occurs following diffusion. The changes in the oxide can be related to the formation of aphyphen;type surface layer on diffused crystals exposed to air, through oxygen adsorption.
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