Search for content and authors
 

Single phase formation mechanism of SexTe100-x binary alloy confirmed by XRD and TEM method

Yong Tae Kim 1Eun Tae Kim 2

1. Korea Institute of Science and Technology, Semiconductor Materials and Devices Laboratory, Seoul 136-791, Korea, South
2. Korea Advanced Institute of Science and Technology (KAIST), Yuseong, Daejeon 305-701, Korea, South

Abstract

High resolution transmission electron microscopy (HR-TEM) and x-ray diffraction (XRD) measurements are done for the SexTe100-x (x=16, 29, 38) thin films crystallized with rapid thermal annealing at 250 °C for 5 min. Composition of each sample is analyzed by Rutherford backscattering spectroscopy and the crystal structures of Se16Te84, Se29Te71 and Se38Te62 thin films are identified as a hexagonal structure of Te basis. Diffraction patterns for each composition are identical, meaning that the structure of the SexTe100-x films does not change with different compositions. Also, there are no peaks addressed to a hexagonal Se structure. But the 2 theta value which is corresponded to the Te {0 1 1} peak increases with the increase of Se content. This means that the interplanar spacing between adjacant Te {0 1 1} planes becomes to be shorter with the Se content. The calculated spacing between Te {0 1 1} planes for Se16Te84 is 3.189 Å, that is 3.162 and 3.134 Å for Se29Te71 and Se38Te62, respectively. From the HR-TEM images of Se16Te84 and Se38Te62, it is found that the interplanar spacing between (0 1 -1) planes of Se16Te84 is longer than that of Se38Te62. This is well agreed with the calculated result from XRD. According to the models for the crystal structures consist of Se and Te basis based on the HR-TEM images and the simulated lattice images, it is indicated that the Se atom substitutes the Te atomic site in the Te hexagonal structure, leads to the variation of plane spacing. Because that the atomic size of Se is smaller than Te, it is plausible that the interplanar spacing between (0 1 -1) planes of Se16Te84 that has less content of Se atoms to substitute the Te atomic sites is longer than that of Se38Te62 in the same hexagonal structure.

 

Legal notice
  • Legal notice:
 

Related papers

Presentation: Oral at E-MRS Fall Meeting 2007, Symposium J, by Yong Tae Kim
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-14 08:02
Revised:   2009-06-07 00:44