研究目的
To investigate the band structure and optical constants of SnS2 single crystals, including absorption, reflection, and transmission spectra, and to determine the nature of electronic transitions and optical properties.
研究成果
The minimal band gap in SnS2 crystals is due to indirect transitions between Γ and M points at 2.403 eV, with direct allowed transitions at 2.623 eV in E||b polarization and forbidden transitions at 2.698 eV in E⊥b polarization. Refractive index ranges from 3 to 4, peaking at 2.6 eV. Optical functions were calculated and electron transitions were localized in the theoretical band structure, confirming the nature of transitions observed.
研究不足
The study is limited to SnS2 crystals of specific hexagonal phase and thicknesses; extrapolation was necessary for Kramers-Kronig analysis in unmeasured spectral regions. The influence of lattice vibrations was neglected, which may affect accuracy.
1：Experimental Design and Method Selection:
The study involved measuring absorption, reflection, and wavelength-modulated transmission spectra of SnS2 crystals in the temperature range of 10 to 300 K. Spectrometers (MDR-2, DFS-32, SDL-1) were used with automated and computerized systems. Kramers-Kronig analysis was applied to calculate optical functions from reflection spectra.
2：Sample Selection and Data Sources:
SnS2 crystals were grown by the gas transport method, with thicknesses ranging from 78 μm to 3 mm, cleaved to obtain mirror surfaces. Samples were selected based on visual recognition of surfaces parallel to the b axis.
3：List of Experimental Equipment and Materials:
Equipment included spectrometers MDR-2, DFS-32, and SDL-1, a closed helium LTS-22 C 330 optical cryogenic system, and automated measurement setups. Materials were SnS2 single crystals.
4：Experimental Procedures and Operational Workflow:
Crystals were placed in the cryogenic system for temperature control. Spectra were measured with spectrometer slits not exceeding 30 μm for high resolution. Interference and wavelength-modulated spectra were recorded, and refractive indices were calculated from interference fringes.
5：Data Analysis Methods:
Data were analyzed using Kramers-Kronig relations to determine optical constants. Refractive indices were calculated from interference spectra using methods described in references.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
