Carbon doping for p‐type GaP and GaPN in molecular beam epitaxy using carbon tetrabromide source

Carbon doping for p -type GaP and GaPN using carbon tetrabromide (CBr4) source in rf plasma molecular beam epitaxy was investigated. The doping concentration could be easily controlled by adjusting CBr4 pressure, and a wide region of hole concentration form ∼1017 to ∼1019 cm-3 was obtained in both GaP and GaPN. It was found that the activation ratio of carbon in GaPN is lower than that in GaP. The hole concentration and mobility in GaPN do not change with nitrogen content at a wide region from 0.5 to 3%. The Hall mobility values in GaP and GaPN were ∼120 and ∼50 cm2/Vs at a hole concentration of ∼1 × 1017 cm-3. Photoluminescence measurement show that the carbon incorporation reduces the intensity of luminescence, and the relative peak intensity decreases with the increase of hole concentration. This implies the existence of carbon-related defects that quench the luminescence (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)