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

Abstract

Defects play an important role in determining the type of carriers as well as in tunning 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 the modified Bridgman method. The correlation between structural defects and the type of dominant charge carriers in crystals is 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. BiTe antisite defects or interstitial Te atoms. We observe that the alteration of charge carriers from electrons to holes has enhanced magnetoresistance from 103% to 224%. The enhancement in magnetoresistance emerges from the 2D multichannel quantum coherent conduction mechanism.