Half-Metallic and Optical Properties of Cu and Cr Codoped AlN

The Half-metallic and optical properties of wurtzite Cu and Cr codoped AlN were investigated by first-principles calculation based on density functional theory (DFT) using the generalized gradient approximation (GGA) for the exchange-correlation potential. It is shown that the Cu and Cr codoped AlN is a typical half-metallic material at the equilibrium lattice constant. As a p-type semiconductor, there exhibits higher hole concentration in Cu and Cr codoped AlN comparing with Cu doped AlN or Cr doped AlN, which indicates a significant increase in TC. This result suggests that it is possible to achieve high TC materials by Cu and Cr codoped AlN. In addition, the band gap of Cu and Cr codoped AlN is reduced and the absorption ability to ultraviolet light is expanded obviously, a noticeable red-shift of the absorption spectra edge is observed in the Cu and Cr codoped system and two new absorption peaks appear at around 28 nm and 225 nm.