Effect of V/III ratio on the optical properties of MOCVD grown undoped GaAs layers

Abstract

A detailed analysis of low temperature photoluminescence (PL) spectroscopy on undoped high quality GaAs is presented. For undoped GaAs epitaxial layers grown by low pressure metal organic chemical vapor deposition under different V/III ratios, an optimum ratio corresponding to a minimum number of shallow impurities was clearly identified. The V/III ratio has strong effect on the optical properties of undoped GaAs epitaxial layers. When the V/III ratio was varied from 45 to 87, the electron concentration, n, of undoped GaAs increased with increasing V/III ratio. Below the V/III ratio of 45 in our case, the sample exhibited a p-type behavior, which has been identified by photoluminescence as well as depth profiling by Electro-chemical Capacitance Voltage (ECV) profiler.