Thermal Conductivity Measurements of Bi2Te3 Nanostructure By Raman Thermography

Single-crystal Bi₂Te₃ nanowire and nanoribbon were synthesized by using a vapor-liquid-solid method with Bi₂Te₃ powder.  The composition and crystalline structure of nanowires were confirmed by energy-dispersive spectroscopy (EDS) and high resolution transmission electron microscopy (HRTEM), respectively.  To investigate the thermal properties of Bi₂Te₃ nanostructure, a nondestructive technique based on Raman temperature mapping was carried out. The red shift of Raman peaks and peak broadening observed as temperature increased.  In addition, the fraction of the laser power absorbed inside the Bi₂Te₃ nanostructure was estimated by optical simulation for calculation of thermal conductivity value (κ).  The obtained thermal conductivity value of Bi₂Te₃ nanowire and nanoribbon is 2.67 Wm^-1K^-1 and 2.81 Wm^-1K^-1, respectively.  The difference in thermal conductivity value between nanowire and nanoribbon is caused by the dimension difference.