Post-annealing induced oxygen vacancy mediated non-polar ZnO films with excellent opto-electronic performance

The considerably enhanced opto-electronic properties of ZnO films with non-polar orientations have been realized by introducing oxygen vacancies. Excitation of oxygen vacancies has been achieved by oxygen-deficient post-annealing treatment. The existence of oxygen vacancies is directly confirmed by cross-sectional XPS and positron annihilation Doppler broadening measurements. An enhanced UV-emission, more simplex green-light emission and sharply decreased electrical resistivity of post-annealed non-polar oriented ZnO films have been acquired in oxygen-deficient atmosphere. I-V measurement indicates that non-polar oriented ZnO/p-Si heterojunction with optimized post-annealing treatment owns an excellent forward electrical transportation and extremely low threshold voltage, have great competitiveness for the commonly used one-dimensional ZnO nanomaterials in photo-electronic field.