Growth and characterization of Bi2Se3 thin films by pulsed laser deposition using alloy target

摘要

Bi2Se3 thin films were deposited on the (100) oriented Si substrates by pulsed laser deposition technique at different substrate temperatures (room temperature – 400 ºC). The effects of the substrate temperature on the structural and electrical properties of the Bi2Se3 films were studied. The film prepared at room temperature showed a very poor polycrystalline structure with the mainly orthorhombic phase. The crystallinity of the films was improved by heating the substrate during the deposition and the crystal phase of the film changed to the rhombohedral phase as the substrate temperature was higher than 200 ºC. The stoichiometry of the films and the chemical state of Bi and Se elements in the films were studied by fitting the Se 3d and the Bi 4d5/2 peaks of the X-ray photoelectron spectra. The hexagonal structure was seen clearly for the film prepared at the substrate temperature of 400 ºC. The surface roughness of the film increased as the substrate temperature was increased. The electrical resistivity of the film decreased from 1x10-3 to 3 x 10-4 Ω cm as the substrate temperature was increased from room temperature to 400 ºC.