Electrical and thermoelectrical properties of Bi2Se3 grown by metal organic chemical vapour deposition technique
Résumé
Bi2Se3 thin films were deposited by metal organic chemical vapour deposition using trimethylbismuth (TMBi) and diethylselenium (DESe) as metal organic sources. Structural properties, electric and thermoelectric results are studied as functions of VI/V ratio (VI/V ratio=DESe partial pressure/TMBi partial pressure). These films always displayed n-type conduction for a VI/V ratio between 14 and 35. The Seebeck coefficient and the carrier concentration vary slightly with the VI/V ratio: - 108 to - 120 μV/K and 2× 1019-4× 1019/cm3, respectively. In contrast, the mobility and the resistivity highly depend on the VI/V ratio. Their values vary from 25 to 140 cm2/V s and 18.2 to 98.5 μΩm, respectively. These studies have allowed us to find the optimal range for the VI/V ratio at growth temperature of 480°C.