| Popis: |
Indium nitride (InN) was grown on both c-plane sapphire and borosilicate glass substrates by reactive evaporation. The reactive evaporation growth technique proved to be simple, cost-effective and offered the advantage of low growth temperature with consistency in growing good quality material with high mobilities and relatively low carrier concentrations. The carrier concentration ranged between 1.59xl0,7cm'3to 4.31x1019 cm' which is in the same range of the reported value for InN grown by MBE and MOVPE. Furthermore, a mobility as high as 2285 cm2V'1s'1 was achieved with the elevation of the substrate temperature to 210 C. The crystalline structure showed a strong correlation with the growth temperature. The films were of polycrystalline nature with hexagonal structure and had a tendency to orientate along the vertical c-axis with the increase in the substrate temperature. The distributed values obtained for lattice parameters were attributed to the nitrogen content in the films and the non-stoichiometry of the material. Compositional and chemical analysis by both x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) confirmed that the material was In-rich material. The role of oxygen was also investigated with SIMS analysis, and estimated a presence of oxygen of 20 at.%. Despite the presence of oxygen level, no evidence of its effect on the band gap was found. Furthermore, the controversy surrounding the band gap was reviewed and investigations on the suggested theories for the discrepancy in the reported values were carried out. |
