氧气分压对反应溅射制备TiO_2薄膜带隙的影响

Effect of Oxygen Partial Pressure on the Band-Gap of the TiO_2 Films Prepared by DC Reactive Sputtering

在不同的氧气分压下 ,用直流反应磁控溅射法制备了玻璃基TiO2 薄膜试样 ,测试了试样的荧光发射光谱。结果表明 ,氧气分压为 0 35和 0 6 5Pa时 ,荧光光谱在 370 ,4 72和 5 14nm处出现发射峰 ;氧气分压为 0 10和 0 15Pa时 ,发射光谱峰出现在 370和 4 90nm处。试样带隙为 3 35eV。0 35和 0 6 5Pa氧气分压下溅射的试样在带隙中有两个分别低于导带底 0 72和 0 94eV的缺陷能级 ,0 10和 0 15Pa氧气分压下溅射的试样在带隙中有一个位于导带底 0 2 3和 1 2 9eV之间的缺陷能带 ;增加氧气分压 ,缺陷能带转变成两个缺陷能级 ,在 0 6 5Pa氧气分压下 ,缺陷能级几乎消失。

TiO2 films have been deposited on glass substrates using DC reactive magnetron sputtering at different oxygen partial pressures from 0.10 to 0.65 Pa. The photoluminescence (PL) spectra of the films were recorded. The results of the PL spectra showed that there were three emission peaks at 370, 472 and 514 nm for the films sputtered at 0.35 and 0.65 Pa, and there were two peaks at 370 and 490 nm for the films sputtered at 0.10 and 0.15 Pa. The band-gap for the films was 3.35 eV. For the films sputtered at 0.35 and 0.65 Pa there were two defect energy levels at 2.63 and 2:41 eV, corresponding to 0.72 and 0.94 eV below conduction band for the band-gap, respectively. For the films sputtered at 0.10 and 0.15 Pa, there was an energy band formed between 3.12 and 2.06 eV, corresponding to 0.23 and 1.29 eV below the conduction band. With increasing the oxygen partial pressure, the defect energy band changed to two energy levels, and the energy levels nearly disappeared for the film sputtered at 0.65 Pa of oxygen partial pressure.