A micro-Raman study of exfoliated few-layered n-type Bi₂ Te_2.7Se_0.3.

ABSTRACT: Previously we showed that the thermoelectric (TE) performance of bulk n-type Bi₂Te_2.7Se_0.3 can be enhanced by subjecting it to a combined process of chemical or mechanical exfoliation (C/ME) followed by a rapid densification and restacking of the exfoliated layers via the spark-plasma-sintering technique (SPS). Here, we present a systematic micro-Raman study of two-dimensional flakes of n-type Bi₂Te_2.7Se_0.3 produced by the C/ME process, as a function of the flake thickness. We found Raman evidence for flakes with: (i) integer number of quintuples which exhibited a strong electron-phonon coupling, and (ii) non-integer number of quintuples, or sub-quintuples which exhibited the forbidden IR active mode due to symmetry lowering

SUBMITTER: Liu F 

PROVIDER: S-EPMC5705651 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature