Structural, spectroscopic and electrical studies of nanostructured porous ZnO thin films prepared by pulsed laser deposition.
Structural, spectroscopic and electrical studies of nanostructured porous ZnO thin films prepared by pulsed laser deposition.
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DOI：
10.1016/j.saa.2013.08.090
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
R. Vinodkumar;I. Navas;K. Porsezian;V. Ganesan;N. Unnikrishnan;V. P. Mahadevan Pillai
中科院分区：
文献类型：
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作者：
R. Vinodkumar;I. Navas;K. Porsezian;V. Ganesan;N. Unnikrishnan;V. P. Mahadevan Pillai
采用脉冲激光烧蚀技术，在氧气氛为0.02 mbar的条件下，在不同的衬底温度(573~973 K)下，在石英衬底上生长了氧化锌薄膜。研究了衬底温度对薄膜的结构、形貌、光学和电学性能的影响。X射线衍射谱和显微拉曼光谱表明，氧化锌具有六方纤锌矿结构，择优取向为(0，0，2)。用德拜-谢勒方程计算了微晶的平均尺寸，发现其平均尺寸在17-29 nm之间。原子力显微镜研究表明，薄膜的表面形貌强烈依赖于衬底温度。紫外可见光谱表明，薄膜在可见光范围内具有很强的透明性。计算得到的光学带隙能随衬底温度的升高而减小。计算了不同衬底温度下制备的氧化锌薄膜的复介电常数、损耗因子以及体积损耗和表面能损耗的分布。所有的薄膜都被发现在自然界中具有高度的渗透性。光致发光光谱表明，所有薄膜在蓝色区域都有很强的发射。薄膜的直流电阻率随衬底温度的升高而减小。对衬底温度573K下制备的薄膜进行了随温度变化的电学测量，结果表明薄膜的电导是热激活的，激活能为0.03911 eV，小于报道的氧化锌薄膜的活化能。
ZnO thin films are grown on quartz substrates at various substrate temperatures (ranging from 573 to 973 K) under an oxygen ambience of 0.02 mbar by using pulsed laser ablation. Influence of substrate temperature on the structural, morphological, optical and electrical properties of the ZnO thin films are investigated. The XRD and micro-Raman spectra reveal the presence of hexagonal wurtzite structure of ZnO with preferred orientation (0 0 2). The particle size is calculated using Debye–Scherer equation and the average size of the crystallites are found to be in the range 17–29 nm. The AFM study reveals that the surface morphology of the film depends strongly on the substrate temperature. UV–Visible transmittance spectra show highly transparent nature of the films in visible region. The calculated optical band gap energy is found to be decrease with increase in substrate temperatures. The complex dielectric constant, the loss factor and the distribution of the volume and surface energy loss of the ZnO thin films prepared at different substrate temperatures are calculated. All the films are found to be highly porous in nature. The PL spectra show very strong emission in the blue region for all the films. The dc electrical resistivity of the film decreases with increase in substrate temperature. The temperature dependent electrical measurements done on the film prepared at substrate temperature 573 K reveals that the electric conduction is thermally activated and the activation energy is found to be 0.03911 eV which is less than the reported values for ZnO films.