Tuning carrier type and density in Bi2Se3 by Ca-doping

TL;DR

This paper demonstrates how calcium doping can systematically control the carrier type and density in Bi2Se3 crystals, achieving low carrier densities and insulating behavior, with detailed electronic property measurements.

Contribution

It introduces a method to tune carrier type and density in Bi2Se3 via Ca-doping, providing insights into electronic properties at low carrier densities.

Findings

Carrier density of ~1x10^17 cm^-3 achieved

Insulating behavior observed at low carrier densities

Band gap and effective mass determined

Abstract

The carrier type and density in Bi2Se3 single crystals are systematically tuned by introducing a calcium (Ca) dopant. A carrier density of ~1x1017 cm-3 which corresponds to ~25 meV in the Fermi energy is obtained in both n- and p-type materials. Electrical transport properties show that the insulating behavior is achieved in low carrier density crystals. In addition, both the band gap and reduced effective mass of carriers are determined.