Role of defects on carrier dynamics and transport mechanism in Bi2Te3 single crystals

TL;DR

This study demonstrates how controlling defects during crystal growth of Bi2Te3 influences whether electrons or holes dominate, affecting transport properties and magnetoresistance through specific defect types.

Contribution

It shows that varying growth kinetics can selectively induce defect types to control carrier dominance in Bi2Te3 single crystals.

Findings

Electrons originate from Te vacancy defects.

Holes are associated with Bi_Te antisite or interstitial Te defects.

Magnetoresistance increases from 103% to 224% with carrier type change.

Abstract

Defects play an important role in determining the type of carriers as well as on tuning the physical properties of layered materials. In this study, we have demonstrated that by varying the growth kinetics one can control the defects and can achieve electrons or holes dominated Bi2Te3 single crystals using modified Bridgman method. The correlation between structural defects and the type of dominant charge carriers in crystals are discussed using X-Ray diffraction and Hall resistivity. Electrons are found to be originating from Te vacancy type defects, while holes are manifested from predominant structural defects viz. Bi_Te antisite defects or interstitial Te atoms. We observe that the alteration of charger carriers from electrons to holes have enhanced magnetoresistance (MR) from 103% to 224%. The enhancement in MR emerges from 2D multichannel quantum coherent conduction mechanism.