Control of antisite defect effect of Sb/sub 2/Te/sub 3/ thin films

Abstract

We have grown Sb/sub 2/Te/sub 3/ thin films on CdTe[111]B and GaAs[111]B substrates by the conventional co-deposition method using molecular beam epitaxy. In order to investigate and reduce the antisite defects, we varied the relative ratio of the flow-rates of Sb and Te. X-ray diffraction patterns (/spl theta/-2/spl theta/ scans) of the films show that they are well aligned with their (00.1) axis normal to the substrates, regardless of the relative flow-rate ratio. The measurement of the rocking curves of the films shows that they are of high quality, despite a rather large lattice mismatch between the substrate and the film deposited at 200/spl deg/C, with a rocking curve FWHM less than 0.17/spl deg/. The change in the relative flow-rate ratios of Te to Sb causes a remarkable shift in the temperature-dependent thermopower, resistivity, and Hall coefficient of the films. These results demonstrate that by controlling the antisite defects, Sb/sub 2/Se/sub 3/ can be a promising thermoelectric material.