Low temperature photoluminescence properties of Zn-doped GaAs

Dimethylzine (DMZn) was used as a p-type dopant in GaAs grown by low pressu re metalorganic chemical vapor deposition (MOCVD). The influence of growth parameters, such as, DMZn mole fractions, growth temperature, trimethylgall ium (TMGa) mole fractions, substrate surfaces on the Zn incorporation have been studied. The surface morphology of the layers was measured by scanning electron microscopy (SEM). The hole concentrations and zinc (Zn) incorpora tion efficiency are studied by using Hall effect, electrochemical capacitan ce voltage (ECV) profiler, and low temperature photoluminescence (LTPL) spe ctroscopy as functions of hole concentration (10(17) - 1.5 x 10(20) cm(-3)) and experimental temperatures (4.2-300 K). The hole concentration increase s with increasing DMZn and TMGa mole fractions and decreases linearly with increasing growth temperature. The main PL peak shifted to lower energy and the full width at half maximum (FWHM) increased with increasing hole conce ntration. An empirical relation for FWHM, Delta Ep, band gap, Eg, and band gap shrinkage, Delta Eg in Zn doped GaAs as a function of hole concentratio n were obtained. These relations are considered a useful tool to determine the hole concentration in Zn doped GaAs by low temperature PL measurement. The hole concentration increases with increasing TMGa mole fraction and the main peak is shifted to lower energy side. (C) 1998 Elsevier Science S.A. All rights reserved.