The Effect of Dopant on the Optical Anisotropic Properties of Layer Semiconductor Rhenium Disulfide
碩士 === 國立臺灣海洋大學 === 電機工程學系 === 97 === The effect of dopants on the optical anisotropy properties of ReS2 layered crystals will be compared and discussed. ReS2 is a layered semiconductor that belongs to the family of the transition-metal dichalcogenides (TMDCs) crystallizing in the distorted octahedr...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2009
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| Online Access: | http://ndltd.ncl.edu.tw/handle/85359150729506082137 |
| Summary: | 碩士 === 國立臺灣海洋大學 === 電機工程學系 === 97 === The effect of dopants on the optical anisotropy properties of ReS2 layered crystals will be compared and discussed. ReS2 is a layered semiconductor that belongs to the family of the transition-metal dichalcogenides (TMDCs) crystallizing in the distorted octahedral layer structure of triclinic symmetry. Their metal–atom sheets exhibit a clustering pattern of “diamond chains”. The atoms comprising the Re4 diamonds are coplanar. The as grown samples exhibit thin dark line in the crystal plane that correspond to the orientation of b axis and is parallel to the cluster chain.
In this work, ReS2 single crystals doped with W or Mo or Nb were grown using chemical vapor transport method with Br2 as the transporting agent. The in-plane anisotropic optical properties of the as grown samples were investigated by polarization-dependent transmittance and piezoreflectance (PzR) with optical polarization along and perpendicular to the crystal b axis. Based on the analysis of polarization-dependent transmittance curves, the temperature dependence of the indirect band gap has been determined. The indirect energy gap of the doped ReS2 shows a slight red-shift with respect to the undoped sample. The polarization-dependent PzR spectra were used for the determination of the excitonic transitions. The parameters that describe the temperature variations of the indirect band-edge transition energies and direct band-edge excitonic transitions were evaluated and discussed.
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