Growth, morphology and electrical transport properties of MOCVD-grown p-InSb

Abstract

p-type InSb was prepared from trimethyl indium and trimethyl antimony at temperatures between 420 and 490 degrees C. A narrow window in the growth conditions of temperature and V/III ratio was found for InSb, with non-uniform, inhomogeneous epilayer growth for conditions other than optimum. Optimum morphologies were achieved for V/III ratios between 2.2 and 2.5 and at a temperature of 450 degrees C and the use of low pressures in the growth of InSb was observed to result in an enhanced uniformity. The InSb prepared displayed type conversion over the range 70-300 K; analysis of the transport properties is then complicated by the contributions from two carriers. Calculations using Fermi-Dirac statistics were carried out, identifying the majority carrier to be holes over the entire temperature range considered. Calculations also identify an acceptor level with activation energy of 16+or-0.5 meV, an acceptor concentration of (2.65+or-0.02)*1017 cm-3, in good agreement with conductivity measurements, and a low-temperature hole mobility of 450 cm2 V-1 s-1. The detailed analysis employing Fermi-Dirac statistics is then extended to determine the temperature dependence of the Fermi level in InSb and InAs for various impurity compositions.