The effect of doping on the non-stoicheiometry of zinc oxide

Abstract

Chemical methods previously described have been applied, with minor modifications, to the analysis of the non-stoicheiometry of polycrystalline zinc oxide which had been doped with gallium or lithium by heating in air. It is shown that, under these conditions, the methods provide a direct measure of electron concentration, and of the concentration of the impurifying element occupying substitutional positions in the zinc oxide lattice. Under the specified conditions of doping, electron concentrations ranged from 6.9 x 10¹⁸ electrons cm^-3 for samples doped with gallium to an electron deficiency of 2.6 x 10¹⁸ holes cm^-3 for lithium-doped samples. The effect of doping on the electrical conductivity is briefly shown. The methods provide a convenient and accurate means of determining rates of substitutional diffusion in zinc oxide. The diffusion coefficient of gallium at 950º was calculated to be 4.7 x 10^-15 cm² sec^-1.