氧化钨多孔薄膜的制备及光学性质

Preparation and Optical Properties of Porous Tungsten Oxide Thin Film

多孔结构可以使氧化钨薄膜的气敏、电致变色等性能得到增强,但目前多孔氧化钨薄膜的制备仍存在困难。本文采用W和Al双靶磁控溅射的方法得到了W-Al合金薄膜后,把合金薄膜浸入NaOH溶液中处理,其中的Al被腐蚀同时W被氧化,从而得到了多孔的氧化钨薄膜。利用SEM观察多孔氧化钨薄膜样品的表面形貌,用XPS分析样品中W的价态,用XRD分析样品的晶体结构,用紫外-可见-近红外分光光度计测量样品的光学性质。结果显示:制得的多孔氧化钨薄膜的平均孔径在100nm左右,呈海绵状疏松结构;薄膜中W的价态以+5价为主;薄膜属于非晶相;在可见光区域,多孔氧化钨薄膜具有较高的透过率,而在近红外区域则具有近似平直的透过率曲线。

Porous tungsten oxide thin film was prepared by a two-step method. Firstly,a W-Al alloy thin film was deposited on a glass substrate by magnetron co-sputtering process.Then the W-Al alloy thin film was immersed into a NaOH solution.The Al component of the alloy film was corroded and W component was oxidized,forming a porous tungsten oxide thin film.Surface morphology,valence state of W,crystal structure and optical properties of the porous tungsten oxide thin film were analyzed by SEM,XPS,XRD and UV-VIS-NIR,respectively. It is found that the porous tungsten oxide film possesses a sponge-like structure, with average pore size of about lOOnm. The W component of the porous film exists mainly in W5＋ valence state, and the crystal structure of the film is amorphous. In the visible region, the transmittance of porous tungsten oxide film is high in contrast with dense tungsten oxide film, and the transmittance curve of porous tungsten oxide thin film is approximate to a flat line in the near infrared region.