Defects in Indium-Related Nitride Compounds and Structural Design of AlN/GaN Superlattices
In this chapter, we focus on two topics related to the electronic and optical properties of III-nitride compounds. By applying of ab initio approach, we can analyze the electronic structures of III-nitride compounds as well as other semiconductors. This is exemplified by theoretical analysis of electronic structures of In-related nitride compounds, which exhibit characteristic behavior originating from the large difference in the covalent radius between In and N atoms. By considering atomic and electronics structures of nitrogen vacancy (VN) in InGaN in detail, the second nearest neighbor In–In interaction are crucial for unusually narrow bandgap of InN. Furthermore, this approach is applied to demonstrate AlN/GaN superlattice in the wurtzite phase with one or two GaN monolayers, which is efficient for near-band-edge c-plane emission of deep-ultraviolet (UV) LEDs. In particular, the emission wavelength is estimated to be 224 nm for the AlN/GaN superlattice with one GaN-monolayer, which is remarkably shorter than that for Al-rich AlGaN alloys. The optical matrix element of such superlattice is found to be 57% relative to the GaN bulk value.
- 3.V.Y. Davydov, A.A. Klochikhin, V.V. Emtsev, S.V. Ivanov, V.V. Vekshin, F. Bechstedt, J. Fürthmuller, H. Harima, A.V. Mudryi, A. Hashimoto, A. Yamamoto, J. Aderhold, J. Graul, E.E. Haller, Band gap of InN and In-rich InxGa1-xN alloys (0.36 < x < 1). Phys. Status Solidi B 230, R4 (2002)CrossRefGoogle Scholar