Temperature Driven Unusual Reversible p‐ to n‐Type Conduction Switching in Bi₂Te_2.7Se_0.3

Abstract

Bismuth telluride based alloys are electronic semiconductors, which exhibit n‐ or p‐type conduction due to the formation of Te vacancies or antisite defects, i.e., substitution of Bi on Te site or vice versa. Here, it is demonstrated that the temperature dependent Seebeck coefficient of Bi2Te2.7Se0.3 exhibits a reversible change in conduction from p‐ to n‐type at temperatures >487 K without exhibiting any structural transformation. The detailed characterization revealed that conversion of BiTe/Se antisite defects into Te vacancies is responsible for the p–n transition. The observed p–n transition makes Bi2Te2.7Se0.3 an ideal candidate for temperature controlled electronic switches.

Ultrathin Conductive Interlayer with High‐Density Antisite Defects for Advanced Lithium–Sulfur Batteries

“…[ 64 ] In addition, there are two other peaks at 159.2 and 164.5 eV, which can be ascribed to the Bi atoms in two different chemical environments: one at the correct position in the lattice while the other occupying the vacant Te site (Bi′ Te ). [ 64,65 ] With adsorption of Li 2 S 6 , all the peaks of Bi 4f shift to lower binding energy. Specifically, the Bi 4f 7/2 and 4f 5/2 peaks appear at correct position (marked with green dotted line) while those of Bi′ Te (marked with blue dotted line) shift to lower binding energy by 0.2 and 0.3 eV, respectively.…”