GaN/AlN Interface Characteristics in Presence of Point Defects

The geometry of point defects in the GaN/AlN interface was calculated in the framework of the cluster approach. The calculations were carried out using two methods: first-principles Hartree-Fock method and the density... [ view full abstract ]

The geometry of point defects in the GaN/AlN interface was calculated in the framework of the cluster approach. The calculations were carried out using two methods: first-principles Hartree-Fock method and the density functional theory with the hybrid functionals B3LYP. This calculation method was realized with the software package GAMESS. The model cluster of GaN/AlN heterointerface with the mixing of gallium and aluminum atoms in the range of 0 – 100 % is under consideration (see Figure).

The comparison of the calculated Ga-Al bond lengths was carried out with the experimental data obtained using EXAFS spectroscopy for GaN/AlN heterostructures. As it follows from the preliminary comparison the bond lengths calculated using the quantum-mechanical first-principles Hartree-Fock method of the self-consistent field are in good agreement with experimental data as opposed to the bond lengths calculated using the density functional theory with the hybrid functionals B3LYP in a combination with Hay-Wadt effective core potentials. As follows from the comparison of calculated and experimental data the most probable locations of nitrogen vacancy in the vicinity of GaN/AlN interface are the location in the GaN/AlN interface and the location in the first Ga layer in respect to the GaN/AlN interface. So, the presence of nitrogen atom vacancy in the heterointerface does not influence on the Al and Ga contacting layers intermixing.

Another types of point defect and structure parameters are discussed in the report.

This work was partialy supported by BRFFR, grant F17RM-024