Tuning of charge carrier density by deposition pressure in Sb-doped Bi2Se3 thin films

•With increase in Ar pressure, carrier density of Sb-doped Bi2Se3 film decreases.•Quantum coherence length increases with increase in Ar pressure.•Solely electron-electron interaction based de-phasing in 50 Pa deposited films.•α of 50 Pa deposited film is −1, indicating two independent transport channels. We report the tunability of charge carrier density in a pulsed laser deposition grown Bi1.95Sb0.05Se3 thin film system as a function of the deposition pressure. Dynamic partial pressure of argon maintained in the chamber during deposition suppresses Se escape, effectively regulating the stoichiometry, which in turn modulates the charge carrier density. With pressure variation, a striking three order change in carrier density is recorded and with additional control through the substrate temperature a carrier density value as low as 2 × 1018 cm−3 is found to be achievable. We observe a systematic evolution of structural, electronic, and magneto-transport properties of the system with variation of deposition pressure. The magneto-transport properties of the films reveal weak antilocalization behavior, analyzing which we have been able to determine the influence of deposition pressure on properties like the de-phasing mechanism involved in the system, the number of effective transport channels, and the coherence length.