The influence of Al concentration on the structural stability, electronic and optical properties of InN semiconductor from first-principles study

Although InN is a promising semiconductor material because of the narrow band gap and high electronic mobility capacity, the influence of Al-doped concentration on the structural, electronic and optical properties of InN semiconductor is unclear. To improve the electronic and optical properties of InN semiconductor, here, we apply the first-principles method to study the influence of Al-doped concentration on the structural stability, electronic and optical properties of InN semiconductor. The calculated result shows that these Al-doped InN semiconductors are thermodynamic stability due to the negative doped formation energy. Here, the thermodynamic stability of the Al-doped InN becomes weak with increasing Al-doped concentration. In particular, three Al-doped InN nitrides are dynamical stability based on the analysis of phonon dispersion. Furthermore, it is found that the calculated band gap of the Al-doped InN is bigger than the parent InN because the additive Al results in band separation between the N-2p state and In-5p state near the Fermi level (E_F). Compared to the parent InN, the additive Al results in adsorption peak migration from the ultraviolet region to the visible light region. In addition, the Al-doping is beneficial to improve the storage optical properties of InN compared to the parent InN. Therefore, we believe that the metal Al can improve the electronic and optical properties of InN semiconductor.