Hall photovoltage deep-level spectroscopy of GaN films - art. no. 205313

Spectroscopy of photoinduced changes in semiconductor Hall voltage is propo sed as a method to characterize deep levels. An analytical expression for t he Hall coefficient as a function of the charge trapped at grain boundaries is derived. The experimental Hall voltage is demonstrated by measuring thi n films of GaN grown on sapphire and is shown to be consistent with the mod el. The Hall voltage spectrum is correlated to spectra from three other dee p-level spectroscopies: photoluminescence, photoconductivity, and surface p hotovoltage, obtained under the same conditions from the same sample. Compa ring spectra from the various spectroscopies shows that the yellow-luminesc ence-related deep states in GaN are charged in equilibrium and discharged b y the exciting photons, and suggests that the blue-luminescence-related sta tes are deep donors positioned 2.8 eV above the valence band and neutral in equilibrium.