Study on the optical and electrical properties of Fe-doped CuAlO2 with first-principles

Fe-doped is an effective method to improve the conductivity of p-type transparent conductive oxide (TCO). In this paper, we performed first-principle calculations to study the effect of Fe-doped on the electrical structure and optical properties of the CuAlO2 crystal. To get accurate results, we used the finite size correction scheme (FNV method) to correct the defect formation energy for charged defects and the hybrid density functional method was used to adjust the band edge. The calculation results show that the formation energy for Fe occupying Al position (marked as FeAl) in CuAlO2 is lower than that for Fe occupying Cu position (marked as FeCu) and FeAl is the easiest one to form. It is also found that Fe-doping can increase the hole concentration of CuAlO2 and thus increasing the conductivity of the CuAlO2 crystal. Furthermore, we have investigated the optical spectrum of Fe-doped CuAlO2 and the absorption peak of CuAlO2 with FeAl∙∙ locates at 2.07 eV, which is close to the experimental data (2.10 eV). It can be inferred that the transmittance of the material decreases and the light absorption increases in the visible range.