Characterization and optoelectronic properties of p-type N-doped CuAlO2 films

This letter reports a technique for increasing the carrier concentration and the conductivity of the p-type CuAlO2 through doping the material with nitrogen. The x-ray photoelectron spectroscopy and the optical band gap analyses suggested that the nitrogen atoms occupying the interstitial sites of the delafossite structure provided the p-type CuAlO2 with an impurity energy level in the energy gap. It was also found that the N-doped CuAlO2 film had its optimum conduction properties when the dopant level reached 1.1 at. %. Here, the carrier concentration was raised from 4.81x10(16) in the undoped film to 2.13x10(17) cm(-3) in the doped film, and the corresponding film's conductivity was increased from 3.8x10(-2) to 5.4x10(-2) (Omega cm)(-1), as compared with the undoped CuAlO2 film. (C) 2007 American Institute of Physics.