  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.
