Doping studies of Ga O . 5 ~ nO . 5 P organometallic vapor-phase epitaxy

Undoped Gllo.s 1110.5 P has been successfully grown by organometallic vapor-phase epitaxy on GaAs substrates with a free-electron concentration of 10 cm -3 and a mobility of 1050 cm;V s in nominally undoped material. The distribution coefficient of indium in the growth of Gllo.s IIlo.sP is nearly to unity. Both nandp-type carrier concentrations of up to 10 19 cm3 have been obtained in the present study. Diethyltelluride and silane are used as n-type dopants. Dimethylzinc is used as the p-type dopant. Te is a very efficient dopant with a distribution coefficient kTe = 54. The photoluminescence (PL) intensity increases with Te doping level to a maximum at n = 2x 10 cm3 • The silicon distribution coefficient is temperature dependent, due to the incomplete pyrolysis of silane at the growth temperature. Si-doped Gllo.s 1110.5 P has a lower PL efficiency than Te-doped samples and is not strongly correlated with carrier concentration. The incorporation efficiency ofZn is low, with kZn = 3.8 X 10, due to the high vapor pressure of Zn at the growth temperature. The PL intensity of Zn-doped Gao.s 1110.5 P also increases with Zn doping level to a maximum atp = 2X 10 cm3 and is comparable to the optimum Te-doped n-type Gao.s II1o.s P. Only a single band-edge PL peak is observed in all cases.