Structural and Optical Properties of ZnO Thin Films Prepared by Molecular Precursor and Sol-Gel Methods
Structural and Optical Properties of ZnO Thin Films Prepared by Molecular Precursor and Sol-Gel Methods
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DOI：
10.3390/cryst10020132
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发表时间：
2020-02-01
期刊：
影响因子：
2.7
通讯作者：
De Leeuw, Nora H.
中科院分区：
文献类型：
--
作者：
Amakali, Theopolina;Daniel, Likius. S.;De Leeuw, Nora H.
氧化锌是一种用途广泛、价格低廉、直接带隙宽的半导体材料，在多个科学技术领域具有广泛的应用前景。在本工作中，我们报道了两种简单、低成本的合成方法，即分子前驱体法(MPM)和溶胶-凝胶法，并成功地在显微镜玻璃衬底上沉积了氧化锌薄膜。对薄膜的结构和光学性能进行了表征。X射线衍射分析表明，薄膜具有高度的c轴(0 0 2)择优取向，具有良好的压电性。原子力显微镜(AFM)的表面粗糙度分析表明，MPM法制备的薄膜表面较粗糙，平均粗糙度(Ra)为2.73 nm，而溶胶-凝胶法制备的薄膜的平均粗糙度为1.55 nm。MPM法制备的薄膜比溶胶-凝胶法制备的薄膜更透明。用溶胶-凝胶法制备的氧化锌薄膜的光学带隙为3.25 eV，与其他作者的测量结果一致。然而，MPM制备的薄膜的光学带隙变宽(3.75 eV)。
Zinc oxide (ZnO) is a versatile and inexpensive semiconductor with a wide direct band gap that has applicability in several scientific and technological fields. In this work, we report the synthesis of ZnO thin films via two simple and low-cost synthesis routes, i.e., the molecular precursor method (MPM) and the sol-gel method, which were deposited successfully on microscope glass substrates. The films were characterized for their structural and optical properties. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for piezoelectric applications. The surface roughness derived from atomic force microscopy (AFM) analysis indicates that films prepared via MPM were relatively rough with an average roughness (Ra) of 2.73 nm compared to those prepared via the sol-gel method (Ra = 1.55 nm). Thin films prepared via MPM were more transparent than those prepared via the sol-gel method. The optical band gap of ZnO thin films obtained via the sol-gel method was 3.25 eV, which falls within the range found by other authors. However, there was a broadening of the optical band gap (3.75 eV) in thin films derived from MPM.