Elaboration of Bi 2Se 3 by metalorganic chemical vapour deposition

Abstract

For the first time, Bi 2Se 3 thin films were elaborated by metalorganic chemical vapour deposition (MOCVD) using trimethylbismuth (TMBi) and diethylselenium (DESe) as metalorganic sources. The MOCVD elaboration of Bi 2Se 3 was carried out in a horizontal reactor for a substrate temperature ( T g) varying from 450°C to 500°C, a total hydrogen flow rate D T=3 l min −1, R VI/V ratio >14 and TMBi partial pressure lower than 1.10 −4 atm. By X-ray diffraction and SEM observation, we noticed the polycrystalline structure of the layers typical preferential c-orientation and confirm the hexagonal structure. The microprobe data indicate that the best stoichiometry of Bi 2Se 3 was achieved. These films always displayed n-type conduction, and the maximum value of thermoelectric power α was found to be close to −120 μV/K.