Hybrid physical–chemical vapor deposition of Bi2Se3 films

Abstract

a b s t r a c t Bi 2 Se 3 thin films were grown on c-plane sapphire substrates by hybrid physical-chemical vapor deposition (HPCVD) using trimethyl bismuth (TMBi) and Se pellets. A Se-rich environment is created by evaporating Se pellets in the vicinity of the substrate, which is used to suppress the formation of Se vacancies. The effects of pre-cracking temperature and substrate/Se temperature on the growth rate, structural and electrical properties of the Bi 2 Se 3 films were investigated. C-axis oriented films were obtained which show a reduction in the carrier concentration as pre-cracking temperature was increased from 290°C (1.6Â 10 19 cm À 3 ) to 350°C (8.4 Â 10 18 cm À 3 ). An additional reduction in carrier concentration (7.28 Â 10 18 cm À 3 ) was observed on increasing the substrate temperature from 200 to 260°C.