Orientation dependence of the Si doping of GaAs grown by molecular beam epitaxy

An optical study of Si-doped GaAs grown on (311)A-, (111)A-, (111)B- and (100)-oriented substrates by molecular beam epitaxy is reported. Raman measurements on these samples indicate good crystalline properties. Electrical characterization reveals an n-type doping of the (111)B and (100) samples and a p-type doping of the (111)A and (311)A samples. Detailed assessment of the low-temperature photoluminescence spectra suggests that the (311)A sample is more compensated than the (111)A sample and that the (111)B is more compensated than the (100) sample.