Hydrogenation of p-type gallium nitride

Hole concentrations of up to 1019 cm−3 have been reported for GaN:Mg films grown by molecular beam epitaxy without any post-growth treatment. Comparing results from Hall measurements and secondary ion mass spectrometry, we observe doping efficiencies of up to 10% at room temperatures in such p-type material. By hydrogenating at temperatures above 500 °C, the hole concentration can be reduced by an order of magnitude. A new photoluminescence line at 3.35 eV is observed after this treatment, both in p-type and unintentionally doped n-type material, which suggests the introduction of a hydrogen-related donor level in GaN.