Electrical and Optical Properties of Nb-doped SrSnO3 Epitaxial Films Deposited by Pulsed Laser Deposition
Electrical and Optical Properties of Nb-doped SrSnO3 Epitaxial Films Deposited by Pulsed Laser Deposition
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脉冲激光沉积Nb掺杂SrSnO_3外延薄膜的电学和光学性质
DOI：
10.1186/s11671-020-03390-1
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发表时间：
2020-08-17
影响因子：
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通讯作者：
Liu, Qinzhuang
中科院分区：
文献类型：
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作者：
Li, Kaifeng;Gao, Qiang;Liu, Qinzhuang
在不同的氧压和衬底温度下，使用脉冲激光沉积在 LaAlO3(001) 单晶衬底上外延生长 Nb 掺杂 SrSnO3 (SSNO) 薄膜。详细研究了薄膜的晶体结构、电学和光学性质。 X射线衍射结果表明，随着氧压的增加，薄膜的晶胞体积逐渐减小，同时保持了外延特性。 X 射线光电子能谱分析证实了 SSNO 薄膜中的 Nb5+ 氧化态。进行霍尔效应测量，在0.2Pa压力和780℃衬底温度下制备的薄膜表现出最低的室温电阻率31.3 m Omega cm和霍尔迁移率3.31cm(2)/Vs，载流子浓度为6.03 x 10(19)/cm(3)。该样品的电阻率随温度变化显示出金属-半导体转变，主要通过电子-电子效应来解释。该薄膜在600-1800nm波长范围内光学透明度大于70%。通过将氧压从20降低到1 x 10(-3)Pa，间接带隙从4.35增加到4.90eV，直接带隙从4.82增加到5.29eV，这可以通过Burstein-Moss效应和高真空中产生的氧空位来解释。
Nb-doped SrSnO3 (SSNO) thin films were epitaxially grown on LaAlO3(001) single-crystal substrates using pulsed laser deposition under various oxygen pressures and substrate temperatures. The crystalline structure, electrical, and optical properties of the films were investigated in detail. X-ray diffraction results show that the cell volume of the films reduces gradually with increasing oxygen pressure while preserving the epitaxial characteristic. X-ray photoelectron spectroscopy analysis confirms the Nb5+ oxidation state in the SSNO films. Hall-effect measurements were performed and the film prepared at 0.2Pa with the 780 degrees C substrate temperature exhibits the lowest room-temperature resistivity of 31.3 m Omega cm and Hall mobility of 3.31cm(2)/Vs with a carrier concentration at 6.03 x 10(19)/cm(3). Temperature-dependent resistivity of this sample displays metal-semiconductor transition and is explained mainly by electron-electron effects. Optical transparency of the films is more than 70% in the wavelength range from 600 to 1800nm. The band gaps increase from 4.35 to 4.90eV for the indirect gap and 4.82 to 5.29eV for the direct by lowering oxygen pressure from 20 to 1 x 10(-3)Pa, which can be interpreted by Burstein-Moss effect and oxygen vacancies generated in the high vacuum.