The effect of dopants on the electrical transport and optical properties of ReSe2 layered crystals

• Main Author: 林鑫成
• Other Authors: 程光蛟
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/71263950005708662772

碩士 === 國立海洋大學 === 電機工程學系 === 91 === ReSe2 is a diamagnetic indirect semiconductor with energy gap around 1.2 eV. ReSe2 crystallized in a distorted 1T-MX2 dichalcogenides phase with clustering of Re4 “diamond” units forming a one-dimensional chain within the van der Waals plane. The diamond chain clusters in the metal sheet of ReSe2 resulted in a lattice distortion from the ideal octahedral layered structure resulting in an optical biaxial character of the compound. Therefore, anisotropic response is expected for linearly polarized light incident normal to the basal plane [E∥(001), k⊥(001)]. In this work, Single crystals of ReSe2 doping with W or Mo are grown using the chemical vapor transport method with Br2 as the transport agent. Both W-doped and Mo-doped ReSe2 formed thin silver-colored, graphite like platelets with up to 2 cm2 in area and 100 μm in thickness. X-ray diffraction has been used to confirm the stoichiometry of the as-grown samples. Resistivity measurements have been carried out to study the electrical transport properties of the single crystals. Estimation of the optical gaps has been accomplished using the transmission spectroscopy. The effect of dopants on the interband transition energies of various features has been probed with the assistance of piezoreflectance measurements. The effect of dopants on the electrical Transport and optical properties of ReSe2 layered crystals will be compared and discussed.