Relationship between Surface Treatment of ZuTe Substrates and Morphology of CdSe Epitaxial Layers in Liquid Phase Epitaxy

The epitaxial layers of CdSe were grown on ZnTe at 560°C by liquid phase epitaxy (LPE) from a Te solution in an open tube apparatus. The morphology of the grown layer was greatly influenced by the smoothness of the substrate surface. The effects of the meltback solution and the chemical etchant on the morphology of the grown layer were investigated. The layer grown with the Cd+Zn alloy as a meltback solution had a smooth and flat surface without hollows between the grown layer and the substrate, although there were some hollows near the interface with Te meltback or without meltback. Chemical etching of the substrate also affected the morphology of the grown layer. Etching with a mixture solution of K2Cr2O7 and HNO3 caused the surface of the ZnTe substrate to become mirrorlike and resulted in the growth of CdSe layers with smoother surfaces.