Structural and optical properties of C–Si codoped p-type and intrinsic AlN crystal

Abstract

C–Si codoped p-type and intrinsic AlN crystals were grown by the sublimation method. The structure and optical characterisation of the AlN crystals were examined. X-ray diffraction shows that the quality of AlN crystals does not change obviously with codoping C and Si. Photoluminescence spectra at room temperature reveal two sharp band-edge lines at 309 and 396 nm from the C–Si codoped AlN and a broad peak around 378 nm from the intrinsic AlN. Then, the authors analysed the structure and composition of AlN crystals with X-ray photoelectron spectroscopy measurement in association with an ab initio electronic structure calculation. Combined the structure and composition of the p-type AlN as well as related theoretical results, the two lines are related to the complexes of VN–CN and CN–SiAl, respectively. Meanwhile, the broad peak in the intrinsic AlN is due to O as the native defect.