The high-temperature transport characteristics of unintentionally doped GaN were investigated by means of high temperature Hall measurements from room temperature to 500C. The increment of electron concentration from room temperature to 500C was found to vary largely for different samples. The dispersion of temperature dependence of electron concentration was found to be directly proportional to the density of dislocations in GaN layers calculated by fitting the full-width at half maxima of the rocking curves in X-ray diffraction measurements. The build-up levels in persistent photoconductivity were also shown to be directly proportional to the density of dislocations. The correlation of X-ray diffraction, Hall and persistent photoconductivity results indicated that the high temperature dependence of electron density in unintentionally doped GaN was directly dislocation related.

Effects of Dislocation on High Temperature Transport Characteristics of Unintentionally Doped GaN. M.J.Wang, B.Shen, F.J.Xu, Y.Wang, J.Xu, S.Huang, Z.J.Yang, Z.X.Qin, G.Y.Zhang: Chinese Physics Letters, 2007, 24[6], 1682-5