The role of dislocation scattering in n-type GaN films

The lateral transport in GaN films produced by electron cyclotron resonance plasma-assisted molecular beam epitaxy doped n type with Si to the levels of ${10}^{15}{\text{–10}}^{20}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-3}}$ was investigated. The room temperature electron mobility versus carrier concentration was found to follow a family of bell-shaped curves consistent with a recently proposed model of scattering by charged dislocations. The mechanism of this scattering was investigated by studying the temperature dependence of the carrier concentration and electron mobility. It was found that in the low carrier concentration region ${\text{(<10}}^{17}\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-3}}\mathrm{),}$ the electron mobility is thermally activated with an activation energy half of that of carrier concentration. This is in agreement with the prediction of the dislocation model.