Ag:ZnO/SiO2 复合薄膜的制备与光学性能

采用溶胶-凝胶法在玻璃衬底上制备Ag掺杂于ZnO层的Ag:ZnO/SiO2(AZSO)复合薄膜,采用XRD、SEM、UV-Vis和PL谱等手段对样品的晶体结构、微观形貌、透过率、吸收率及光致发光性能等进行表征,并观察了掺Ag量对复合薄膜光学性能的影响。XRD结果表明:样品经300℃退火处理后出现ZnO及单质Ag衍射峰;由SEM结果可观察到AZSO复合薄膜颗粒分散均匀,表面致密,其断面照片显示了薄膜的双层结构。UV-Vis吸收光谱结果表明:随着复合薄膜中Ag含量的增加,Ag与ZnO之间的电子转移及Ag颗粒的变大促使Ag的特征吸收峰呈现红移和宽化,样品的透过率也随之降低,吸收边向短波长方向移动,禁带宽度减小。PL谱结果表明:由于Ag的掺入减少了ZnO内空穴浓度并对复合薄膜的结构缺陷进行补偿,以及Ag在440nm附近的特征吸收,降低了复合薄膜的发光强度。

Preparation and Optical Properties of Ag : ZnO/SiO2 Thin Composite Films

The thin Ag : ZnO/SiO2 (AZSO)composite films with Ag doped in ZnO layer were deposited on glass substrates by means of sol-gel method. The crystal structure, microstructure, transmission, absorbance and photoluminescent properties of the samples were characterized by XRD, SEM, UV-Vis and PL, respectively. And the properties of thin composite films under the influence of different Ag contents were also discussed. The results of XRD indicated that there are diffraction peaks of ZnO and Ag after annealed in air at 300 ℃. The results of SEM showed that the film is uniformity and compact, and two-layer structure can be observed from the cross-sectional micrographs. The results of UV-Vis indicated that as the content of Ag increasing, the absorption peaks have red shift and widen because of the electron transfer between Ag and ZnO and the particle size of Ag becoming larger. The transmission of the thin composite films weakens as increasing the content of Ag, and optical absorption edges move to short wavelength. And band gaps of the composite films diminish, too. The PL spectra shows that photoluminescent intensity of the films in the section of ultraviolet and visible region weakens with increasing the content of Ag, this is owed to the reduction of the hole concentration and the compensation of structural defects caused by the doping of Ag and Ags absorption at 440 nm.