Zinc doped GaAs epitaxial layers MOVPE grown by liquid metalorganic sources

The properties of Zinc-doped GaAs, grown by MOVPE employing the tertiary buthyl arsine precursor, were studied as a function of the doping level, comprised within the (1 × 1016 – 7 × 1019 cm–3) range. Hall effect measurements were performed as a function of temperature; the simultaneous analysis of the Hall hole density and Hall mobility gave the effective doping concentration, the thermal ionisation energy of the acceptor impurities and the compensation ratio. Fast Fourier Transform Photoluminescence measurements were performed on the GaAs layers; the results were correlated with those obtained from the electrical analysis. A comparison of the obtained data with the results of an analogous investigation, previously performed on intrinsically Carbon doped GaAs layers, allowed the following conclusions: a) the GaAs layers exhibit a low content of non-intentional impurities (<1014 cm–3); b) both Zinc and Carbon show a low compensation ratio; c) both Carbon and Zinc doped layers show electrical and optical properties comparable with the state of the art; d) Carbon intrinsic doping appears preferable for low-medium carrier concentrations, while Zinc appears preferable for medium-high carrier concentrations (higher than about 5 × 1017 cm–3). (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)