INFLUENCE OF ANNEALING TREATMENT ON THE PHYSICAL PROPERTIES OF InAlN FILMS

Abstract

In this work, pure indium and aluminum targets were co-sputtered in a reactive argon–nitrogen environment at 200°C to deposit InAlN film on the GaAs substrate in the presence of a ZnO buffer layer. The as-grown film was annealed at 750°C for 1 h in a high temperature furnace under nitrogen ambient. XRD pattern of the as-grown film did not display any diffraction peak relating to the InAlN due to its poor structural crystallinity, however, the annealed film exhibited InAlN diffraction peaks corresponding to (002), (101) and (102) planes. A significant increase in the grain size and the surface roughness was observed after the films' annealing. Raman spectroscopy revealed A1 (LO) and E2 (high) phonon modes whereas the PL analysis showed a luminescence peak at 2 eV in the annealed film. The Hall measurements indicated an increase in the carrier concentration and electron mobility after the annealing which was accompanied by a decrease in electrical resistivity of the film. The dark current–voltage (I–V) characteristics of the as-grown and the annealed films were also recorded to investigate the barrier height and the ideality factor.