原子层沉积低温制备高取向锐钛矿TiO_2薄膜

Synthesis and Characterization of Highly Oriented Anatase-Phased TiO_2 Thin Film by Atomic Layer Deposition

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。

The highlyoriented,anatase-phased Ti O2 thin filmswere synthesized by atomic layer deposition（ALD） on substrates of silicon and quartz glass. The effect of the annealing temperature in N2 atmosphere on the microstructures,phase-structures and optical properties was investigated with X-ray diffraction,atomic force microscopy,field emission scanning electron microscopy and ultraviolet-visible transmission spectroscopy. The results show that the annealing temperature strongly affects the microstructures and optical bandgap of the ALD anatase-phased Ti O2 thin film. To be specific,an increase of the annealing temperature from 500 to 600℃ roughened the surfaces,increased the grain size,slightly widened the optical bandgap,decreased the transmittance,and blue-shifted the absorption edge of the as-deposited,highly oriented,anatase-phased Ti O2 thin films. Possible mechanisms responsible for the observation were also tentatively discussed.