Fabrication, characterization and optical properties of Au-decorated Bi2Se3 nanoplatelets
Chih-Chiang Wang, Yu-Sung Chang, Pao Tai Lin, Fuh‐Sheng Shieu, Han‐Chang Shih
Abstract
Abstract Au-decorated Bi 2 Se 3 nanoplatelet heterostructures are fabricated by a two-step process of thermal CVD at 600 °C and magnetron sputtering at room-temperature. The crystal structures and binding energies of rhombohedral Bi 2 Se 3 and FCC Au are determined by XRD, HRTEM, XPS, and Raman spectroscopy. XPS and Raman spectroscopy reveal the interaction between Au and Bi 2 Se 3 by shifting in the binding energies of Au–Au, Au–Se and Bi–Se bonds and the wavenumber of A 1g 2 and E g 2 modes. Au-decorated Bi 2 Se 3 nanoplatelet heterostructures are observed using FESEM, and confirmed by XPS, Raman spectroscopy, and HRTEM imaging. Their optical band gap of the Au-decorated Bi 2 Se 3 nanoplatelet heterostructures increases with Au thickness about 1.92-fold as much as that of pristine Bi 2 Se 3 (0.39 eV), owing to the Burstein-Moss effect. The optical absorptance of the Au-decorated Bi 2 Se 3 nanoplatelet heterostructures revealed increment with wavelength from 200 to 500 nm and decrement with increasing wavelength from 500 to 800 nm.