Microwave hydrogen plasma annealing to improve electrical and optical properties of aluminum doped zinc oxide films

To investigate whether microwave hydrogen plasma can improve the electrical and optical properties of aluminum doped zinc oxide (AZO) films or not, AZO films prepared with different substrate temperature were treated with microwave hydrogen plasma. The AZO films were post-treated by one 2.45 GHz microwave hydrogen plasma system with 25 torr, 700 W and 10 minutes. It was observed the electrical and optical properties of all AZO films prepared with different substrate temperatures were apparently improved with microwave hydrogen plasma. Taking 200°C produced AZO films as an example, the electrical resistivity decreases 43% and the average optical transmittance increases 7% respectively. Microwave hydrogen plasma makes AZO films recrystallization like process from measured results of X-ray diffraction, scanning electron micrograph and transmission electron micrograph. The oxygen adsorption on grain boundary of AZO films after microwave hydrogen plasma apparently decreases observed from results of X-ray photoelectron spectroscopy. The above two phenomena may be the mechanism why microwave hydrogen plasma cam improve the electrical and optical properties of AZO films. This work contributes to industries like touch panel, solar cells. etc. which transparent conductive films belong to the industry product´s component.