Annealing effects on the cathodoluminescence properties of individual ZnO nanowire

Annealing effects on cathodoluminescence of single zinc oxide nanowire are investigated. It is found that ultraviolet emission is gradually decreased and further disappears with temperatures in all the atmospheres. Deep-level emission is blue-shift with temperature in both argon and vacuum, compared with fresh nanowire. Oxygen vacancies are the main defects for the blue-shift in the oxygen-deficient condition such as argon and vacuum. However, deep-level emission is red-shift in oxygen atmosphere with temperature. It is thought that complex defects zinc vacancies and oxygen interstitials should be responsible for the interesting red-shift of deep-level emission.