Hydrogen In Group-III Nitrides: An Ion Beam Analysis Study

The doping mechanisms of InN, a promising material for novel optoelectronic and electronic devices, are still not well understood. Unintentional hydrogen doping is one possibility that could explain the unintentional n-type conductivity in high-quality nominally undoped InN films. We measured a series of state-of-the-art InN samples grown by molecular beam epitaxy with 2 MeV 4He-ERDA and RBS, showing the presence of relatively high amounts of hydrogen not only at the surface, but also in a deeper layer. Strong depletion of hydrogen due to the analysing beam was observed and taken into account in the analysis. Here, we report on the details of the analysis and show how the results correlate with the free-electron concentrations of the samples.