The effect of Al and Gd doping on the structure, microstructure and thermal expansion of gallium nitride (GaN)

Abstract

The changes in the crystal structure, microstructure and thermal expansion occurred upon doping GaN with Al or Gd have been investigated by X-ray diffraction technique. The results showed that Al as well as Gd atoms are accommodated interstitially but in different interstitial positions in the GaN lattice. Anisotropic crystallite size and microstrain are found for the three samples - pure, Al and Gd doped GaN. Also anisotropic thermal expansion is found for the different temperatures ranges (-193, -100, 25, 100, 200). The changes obtained in crystallite size, microstrain and lattice thermal expansion were correlated with the structural changes produced by doping. © by Oldenbourg Wissenschaftsverlag.