微量Al掺杂对溅射于玻璃衬底的SnO2 薄膜结构及光学特性的影响

Effect of Low-Dose Al Doping on Structure and Optical Properties of Sputtered SnO2 Thin Films on Slide Glass

摘要:

采用射频（RF）磁控溅射法在玻璃衬底上制备了低浓度Al掺杂（≤1mol%）的SnO₂系列薄膜。通过X射线衍射、扫描电镜、紫外-红外光谱仪及光致发光（PL）实验，展现了薄膜的晶体结构及光学特性。结果表明：当Al浓度增加时，薄膜晶格常数c减小，表明Al原子成功替代Sn原子并产生了大量的氧空位。在400~800 nm的可见光范围，薄膜的平均透射率可达88%以上。当Al浓度持续增加时，由于Burstein-Moss（BM）效应使薄膜带隙增宽。此外，测量发现，在265 nm波长的光激发下，所制备薄膜的PL谱具有典型的近边带和深能级辐射发光，其峰值随Al浓度的增加而增大。

Abstract:

A series of SnO₂ thin films doped with low-dose Al (≤1mol%) were prepared on slide glass substrates by radio frequency (RF) magnetron sputtering. The crystal structure and optical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-IR spectrometer, and photoluminescence (PL) measurements. Results show that the lattice constant c decreases with increasing the Al content, which implies that Al atoms are successfully introduced into the SnO₂ and occupy the Sn sites, and large number of oxygen vacancies are generated. The average transmittance values are higher than 88% within the visible spectral region (400~800 nm) for all the films. The bandgap broadens when the Al percentage increases, which is dominated by the Burstein-Moss (BM) effect. The PL spectra of these films have near band edge and deep level emission under the radiation excitation of 265 nm wavelength. The observed intensity of these peaks increases consistently with increasing the Al percentage.