Doping studies of Ga0.5In0.5P organometallic vapor-phase epitaxy

Abstract
Undoped Ga0.5In0.5P has been successfully grown by organometallic vapor‐phase epitaxy on GaAs substrates with a free‐electron concentration of 1016 cm3 and a mobility of 1050 cm2/V s in nominally undoped material. The distribution coefficient of indium in the growth of Ga0.5In0.5P is nearly to unity. Both n‐ and p‐type carrier concentrations of up to 1019 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=2×1018 cm3. The silicon distribution coefficient is temperature dependent, due to the incomplete pyrolysis of silane at the growth temperature. Si‐doped Ga0.5In0.5P has a lower PL efficiency than Te‐doped samples and is not strongly correlated with carrier concentration. The incorporation efficiency of Zn is low, with kZn =3.8×103, due to the high vapor pressure of Zn at the growth temperature. The PL intensity of Zn‐doped Ga0.5In0.5P also increases with Zn doping level to a maximum at p=2×1018 cm3 and is comparable to the optimum Te‐doped n‐type Ga0.5In0.5P. Only a single band‐edge PL peak is observed in all cases.

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