Li Kaifeng, Gao Qiang, Zhao Li, Liu Qinzhuang
School of Physics and Electronic Information, Huaibei Normal University, Huaibei, 235000, People's Republic of China.
Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation, Huaibei Normal University, Huaibei, 235000, People's Republic of China.
Nanoscale Res Lett. 2020 Aug 17;15(1):164. doi: 10.1186/s11671-020-03390-1.
Nb-doped SrSnO (SSNO) thin films were epitaxially grown on LaAlO(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 Nb oxidation state in the SSNO films. Hall-effect measurements were performed and the film prepared at 0.2 Pa with the 780 °C substrate temperature exhibits the lowest room-temperature resistivity of 31.3 mΩcm and Hall mobility of 3.31 cm/Vs with a carrier concentration at 6.03 × 10/cm. 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 1800 nm. The band gaps increase from 4.35 to 4.90 eV for the indirect gap and 4.82 to 5.29 eV for the direct by lowering oxygen pressure from 20 to 1 × 10 Pa, which can be interpreted by Burstein-Moss effect and oxygen vacancies generated in the high vacuum.
采用脉冲激光沉积法，在不同氧压和衬底温度下，在LaAlO(001)单晶衬底上外延生长了掺铌的SrSnO（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，薄膜的晶胞体积随氧压的增加而逐渐减小，同时保持外延特性。X射线光电子能谱分析证实了SSNO薄膜中铌的氧化态。进行了霍尔效应测量，在0.2 Pa和780 °C衬底温度下制备的薄膜在室温下表现出最低的电阻率31.3 mΩcm和霍尔迁移率3.31 cm²/Vs，载流子浓度为6.03×10¹⁸/cm³。该样品的电阻率随温度变化呈现金属-半导体转变，主要由电子-电子效应解释。在600至1800 nm波长范围内，薄膜的光学透明度超过70%。通过将氧压从20 Pa降低到1×10⁻⁵ Pa，间接带隙从4.35 eV增加到4.90 eV，直接带隙从4.82 eV增加到5.29 eV，这可以用伯斯坦-莫斯效应和高真空中产生的氧空位来解释。
