The role of annealing conditions on the low temperature photoluminescence properties of CuAlO2

CuAlO2 films and powder are prepared using different annealing conditions such as temperature and atmosphere. The effects of varying these parameters on the optical properties including Raman and low temperature photoluminescence, meta-stability and defect emission are examined. We find evidence that the blue emission may result from oxygen vacancies and that the meta-stability arises from Cu+-Cu+ interactions involving excess copper introduced during the annealing steps.