ABSTRACT

Bi2Se3 thin film was prepared using thermal evaporation . Structure and surface topography were investigated using both of Diffraction Electron Microscope (DEM) and Transmission Electron Microscope (TEM). Optical results confirmed that thin film has a direct energy gap. Moreover, the values for all of oscillating energy (Eo), dispersion energy (Ed) and ratio of the free carrier concentration on the effective mass (N/m*) were determined optically. The dielectric constant (ε\) and tangent loss (ε\) were calculated. The density of states (DOS) for both of valence band (Nv) and conduction band (Nc) and also position of Fermi level were determined. The nonlinear optical results such as third-order optical susceptibility (χ(3)), refractive index (n2) and absorption coefficient (βc) were determined. The influence of temperature on IV results was studied; finally the dependence of all of Dispersion factor (D), parallel inductance (Lp) and Seebeck coefficient (S) values on temperature for this film was studied.

摘要

采用热蒸发法制备了Bi2Se3薄膜。使用衍射电子显微镜 (DEM) 和透射电子显微镜 (TEM) 研究结构和表面形貌。光学结果证实薄膜具有直接的能隙。此外，所有的振荡能量(Eo)、色散能量(Ed)和自由载流子浓度与有效质量的比值(N/m*)都通过光学方法确定。计算介电常数 (ε\) 和正切损耗 (ε\)。确定了价带 (Nv) 和导带 (Nc) 的态密度 (DOS) 以及费米能级的位置。确定了非线性光学结果，例如三阶光学敏感性（χ（3）），折射率（n2）和吸收系数（βc）。研究了温度对IV结果的影响；