Annealing is important in semiconductor process.There are some reports on the annealing of ZnO film.Annealing can affect various properties of ZnO films

such as electrical property

optical property and crystalline property.But there still has no complete mechanism of the effects of annealing on properties of ZnO films.The deep-level green emission exists in ZnO films often

and the views on the origin of the green emission has no consistent.Aim to the situation

we systematically study the effects of oxygen and nitrogen annealing on luminescent property of high crystalline quality ZnO films grown on Al

2

O

3

(0001) by atmospheric pressure MOCVD.Two sets of small Sample 1 and Sample 2 cut off from ZnO as-grown films are used to be annealed in oxygen and nitrogen

respectively.There is a strong ultraviolet emission at 377 nm and a green emission at about 525 nm for Sample 1 and a strong ultraviolet emission at 377 nm for Sample 2.Then Sample 1 and Sample 2 are annealed for 1 h at 400

500

600

700

800 ℃ in sequence in oxygen and nitrogen

respectively.After annealed for 1 h at every temperature

the luminescent property of every Sample was measured by excitation with 325 nm line of He-Cd laser.Research results show that the deep-level emission at 525 nm vanished as annealed at 500 ℃ in oxygen

but not disappeared as annealed at 500 ℃ in nitrogen.Above 700 ℃

there appeared a new green emission at about 500 nm for Sample 1 and Sample 2 whether annealed in oxygen or in nitrogen.Up to 800 ℃

the ultraviolet emission became very weak

the deep-level emission get very strong

and the peak position of deep-level emission become wider at about 500~525 nm.When all annealed Samples and as-grown Sample 1 were etched by ICP for 15 min

the deep level emissions at 525 nm and 500~525 nm vanished

and the ultraviolet emissions became very strong.These results show that there was large effect on deep-level emission of ZnO films by annealing ambience below 700 ℃;while exceeding to 700 ℃

there was obvious effect on luminescence of ZnO thin film by annealing temperature

but the influence of annealing ambience is no obvious.The deep-level emission at 525 nm is relevant to the surface state of ZnO films

and its origin was discussed by the influence of annealing on the luminescent properties of ZnO thin film.