Effects of hydrogen on the electronic properties of Ga(AsBi) alloys

The effects of hydrogen incorporation on the electronic properties of Ga(AsBi) alloys are investigated in a wide range of Bi-concentration (0.6% <= x <= 10.6%) by Hall effect measurements in magnetic fields up to 14 T and by photoluminescence spectroscopy. For all the investigated Bi-concentrations, we report the passivation of Bi-induced shallow acceptor levels-responsible for the native p-type conductivity in Ga(AsBi)-and a tenfold increase of the hole mobility upon hydrogen incorporation in the host lattice. The emission energy is, instead, negligibly affected by hydrogenation, indicating that the narrowing of the band-gap energy with Bi and the native p-type conductivity are two uncorrelated effects arising from different Bi-induced electronic levels. Passivation by hydrogen of the shallow Bi-acceptor levels makes also possible to identify deep Bi-acceptor states. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768237]