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利用原子层沉积(ALD)法分别在Si和石英衬底上制备了Ti O_2薄膜,并在N2氛围下对Ti O_2薄膜样品进行退火处理。采用X射线衍射、原子力显微镜和场发扫描电子显微镜对不同退火温度下样品晶体结构、表面形貌进行了分析。利用紫外-可见分光光度计对不同退火温度下的Ti O_2薄膜进行了光学性能测试,并分析了退火温度对其光学带隙的影响。发现利用ALD方法制备的沉积态Ti O_2薄膜为高度择优取向的锐钛矿结构;当退火温度升高到600℃时,Ti O_2薄膜晶体结构类型仍为锐钛矿型,晶粒略有变大;退火态Ti O_2薄膜粗糙度比沉积态Ti O_2薄膜的粗糙度大,而且粗糙度随退火温度升高而增大。根据薄膜的透射光谱拟合了光学带隙,退火后薄膜禁带宽度略有变宽,吸收边缘发生蓝移。
Ti O 2 thin films were prepared on Si and quartz substrates respectively by atomic layer deposition (ALD) method. The Ti O 2 thin films were annealed under N2 atmosphere. X-ray diffraction, atomic force microscopy and field emission scanning electron microscopy were used to analyze the crystal structure and surface morphology of the samples at different annealing temperatures. The optical properties of Ti O_2 thin films with different annealing temperature were tested by UV-visible spectrophotometer, and the influence of annealing temperature on the optical band gap was analyzed. The results show that the as-deposited Ti O_2 thin films deposited by the ALD method are highly preferentially oriented anatase. When the annealing temperature is raised to 600 ℃, the crystal structure of Ti O_2 thin films is still anatase, The roughness of annealed Ti O_2 thin films is larger than that of the as-deposited Ti O_2 thin films, and the roughness increases with the annealing temperature. The optical bandgap was fitted according to the transmission spectrum of the film. After annealing, the forbidden band width slightly widened and the absorption edge shifted blue.