退火温度对旋涂法制备SnO_2薄膜性能的影响

采用旋涂法在玻璃基底上制备SnO_2薄膜,通过原子力显微镜(AFM)、X射线反射(XRR)、傅氏转换红外线光谱仪(FT-IR)、X射线衍射(XRD)、紫外-可见分光光度计、四探针、开尔文探针系统对薄膜的表面形貌、结构及光学特性、电学特性进行分析,探讨了退火温度对薄膜质量的影响及作用机制。研究发现:随着退火温度升高,薄膜厚度和有机成分杂质减小,薄膜密度递增,但薄膜表面粗糙度有所上升;当退火温度升高至500℃时,薄膜结构由非晶转变为结晶,其主要晶面为氧化锡的(110)、(101)和(211)晶面。旋涂法制备的氧化锡薄膜在可见光区域的平均透光率在90%以上,随着退火温度上升,薄膜在400～800 nm波段的透光率先减小后增大,薄膜的带隙宽度分别为3. 840 eV(沉积态薄膜)、3. 792 eV(100℃)、3. 690 eV(300℃)和3. 768eV(500℃);薄膜的电导率也随着退火温度升高而增加,在500℃时电导率高达916 S/m;薄膜的功函数先增大后减小,分别为(4. 61±0. 005) eV(沉积态薄膜)、(4. 64±0. 005) eV(100℃)、(4. 82±0. 025) eV(300℃)、(4. 78±0. 065) eV(500℃)。

Effect of Annealing Temperature on Properties of SnO2 Thin Films Prepared by Spin Coating

Tin oxide thin films were prepared on glass substrates by spin coating, then, films were annealed at different temperatures in the air. The morphology, structural characteristics, optical properties and electrical properties of the films were characterized by atomic force microscope(AFM), X-ray reflection system(XRR), FT-IR, X-ray diffraction(XRD), UV-visible spectrophotometer, four-probe tester and Kelvin Probe, and the effect of annealing temperature on the quality of film and its mechanism have been studied. The results show that, as the annealing temperature increases, the thickness of the films decreases, the content of organic in films reduces, and the density of the films increases, however, the surface roughness of the film increases. When the annealing temperature is 500℃, SnO₂ crystals appear on the film, the (101), (110), (211) crystal phases appear. Transmittance of samples in the visible light region is above 90%. As the annealing temperature increases, the transmittance of the film in 400-800 nm band decreases first and then increases, and bandgap widths of the films are 3.840 eV(as-deposited), 3.792 eV(100℃), 3.690 eV(300℃), and 3.768 eV(500℃); the conductivity of the film increases, and the conductivity reaches 916 S/m at 500℃; the work function of the film increases and then decreases, and work function of the films is (4.61±0.005) eV(as-deposited), (4.64±0.005) eV(100℃), (4.82±0.025) eV(300℃), (4.78±0.065) eV(500℃).