Hot rolling process for texture development and grain refinement of n-type Bi2Te3 alloys

Abstract

We employed a hot rolling process to modulate the n-type Bi2Te2.82Se0.18 microstructure. The as-quenched Bi2Te2.82Se0.18 ingot was hot-rolled immediately after heating at 773 K for 1 h. The reduction ratio in the hot rolling process was controlled by changing the rolling gap in a range from 2 mm to 5 mm. With the increase in reduction ratio, the (00 l) planes of Bi2Te2.82Se0.18, which have a higher carrier mobility, were more aligned parallel to the rolling direction and grain refinement was accelerated. Such changes in structural properties led to a drastic enhancement in carrier mobility and increased electron concentration. Consequently, the electrical conductivity of Bi2Te2.82Se0.18 was enhanced by the hot rolling process.