TOPOLOGICAL INSULATOR BI2TE3: SYNTHESIS, OPTICAL PROPERTIES AND ENERGY APPLICATIONS

Abstract

TOPOLOGICAL INSULATORS SUCH AS BISMUTH TELLURIDE (BI2TE3) POSSESS PECULIAR PROPERTIES SUCH AS METALLIC SURFACE STATES WITH INSULATING BULK. IN THIS THESIS, SYNTHESIS OF BI2TE3 HEXAGONAL NANOPLATES WITH WELL-DEFINED SHAPES AND SIZES WAS ACHIEVED BY CAREFULLY TUNING THE EXPERIMENT CONDITIONS AND THE GROWTH MECHANISM WAS SYSTEMATICALLY INVESTIGATED. THE SURFACE PLASMONS OF THE SYNTHESIZED BI2TE3 NANOPLATES WERE STUDIED USING ELECTRON ENERGY LOSS SPECTROSCOPY AND REAL SPACE IMAGING OF SURFACE PLASMONS OF TOPOLOGICAL INSULATOR WAS PERFORMED USING SCANNING NEAR-FIELD MICROSCOPY. THE PLASMONIC PROPERTIES AND SURFACE STATES OF BI2TE3 WERE EXPLOITED IN SILICON/POLYMER HYBRID SOLAR CELL AND AN OVERALL POWER CONVERSION EFFICIENCY OF 11.6 % COULD BE OBTAINED, WHICH WAS AN IMPROVEMENT OF 26% OVER THE REFERENCE. FINALLY, THE TERAHERTZ RESPONSE OF BI2TE3 WAS MEASURED AND ITS OPTICAL PARAMETERS IN THE TERAHERTZ REGIME WERE EXTRACTED. TEMPERATURE AND FREQUENCY DEPENDENCE TERAHERTZ MEASUREMENTS REVEALE