Chemical Vapor Growth of ZnTe on GaAs by the Closed-Tube Method

Abstract

The epitaxial growth of ZnTe on a GaAs (100) surface by a closed-tube chemical vapor transport method in the ZnTe–GaAs–I2 system was investigated. The transport and growth rates of ZnTe and the crystalline quality and electrical properties of grown ZnTe layers are described here as functions of the iodine concentration (MI2 ) and the substrate temperature (Ts). The transport and growth rates have a maximum value as a function of MI2 , and increase with increasing Ts. Thermodynamic calculations suggest that gallium iodide plays an important role in the ZnTe–GaAs–I2 system. It has been found that epitaxial ZnTe layers can be grown even at the very low substrate temperature of 547°C. The ZnTe surfaces grown at 650°C were smooth and mirror-like. The resistivity of the grown ZnTe has a tendency to increase with decreasing iodine concentration and substrate temperature. Typical values of the resistivity and the mobility of the ZnTe layer grown at 650°C were 5.2×102 Ω cm and 90 cm2/V·s respectively at room temperature.