The Preparation and Properties of Vapor-Deposited Epitaxial J^l-^x "oonL^r?ine and PhosPhine

Single crystal GaAsl-zPx layers have been grown epitaxially from the vapor phase in a novel apparatus, using gaseous arsine and phosphine as sources of arsenic and phosphorus. These layers exhibit the highest quality, and the widest range of controlled resistivity et reported for solid solutions in this system. Vegard's law is obeyed over the entire composition range. At room temperature, the change from a direct to an indirect transition across the band gap occurs at the value, x = 0.44. Electron mobilities in these layers are high; a sample containing 27 % GaP, for instance, had a room temper-ature mobility of 4900 cm2/v-sec, and a 69 % gallium phosphide alloy had a mobility of 700 cm2/v-sec at room temperature. Both n- and p-type doping have been obtained, with hydrogen selenide gas and zinc vapor as the sources of donor and acceptor impurities, respectively. In this apparatus it is also easy to prepare multi layered structures incorporating layers of different resistivity and/or composition