Optical and Electrical Properties of Sol鈥揋el Derived Ba1鈥?i>xLaxSnO3 Transparent Conducting Films for Potential Optoelectronic Applications
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- 作者：Chao Shan ; Ting Huang ; Jinzhong Zhang ; Meijie Han ; Yawei Li ; Zhigao Hu ; Junhao Chu
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：April 3, 2014
- 年：2014
- 卷：118
- 期：13
- 页码：6994-7001
- 全文大小：376K
- 年卷期：v.118,no.13(April 3, 2014)
- ISSN：1932-7455
文摘
Perovskite-structured Ba1鈥?i>xLaxSnO3 (BLSO, x = 0鈥?.10) films have been directly deposited on (0001) sapphire substrates by a sol鈥揼el method. The effects of La substitution on the microstructure, morphology, and carrier density of the BLSO films have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and Hall-effect measurement. XRD analysis shows that all of the films are of a single perovskite phase and the calculated lattice constants agree well with the theoretical lattice parameters. The AFM and SEM pictures show that the BLSO films do not contain cracks with the root-mean-square surface roughness of 2 nm. Temperature dependent conductivity behavior suggests that BLSO films do have a metallic-like conduction, but the resistivity in poly samples is dominated by grain boundary scattering and ionized-dopant scattering. The films exhibit high transparency with more than 80% in the visible region, which is due to the prohibition of electron transition from the conduction band minimum to the second conduction band. Dielectric functions in photon energy of 0.5鈥?.5 eV can be uniquely extracted by fitting transmittance spectra with the double Tauc-Lorentz and Drude model. It was found that there are two interband transitions (about 4 and 6 eV) and the peak energies increase linearly with increasing La concentration. Far-infrared reflectance spectra was measured in the frequency range of 50鈥?00 cm鈥? and three main reflection bands can be observed. The phonon strength of BLSO films decreases with increasing La concentration.