"Investigation of the local structure of
As-related acceptor centres in InSe by
means of fluorescence-detected XAS
"
J Pellicer-Porres, Ch Ferrer-Roca, A Segura, L Jacquamet
and A Chevy
Semiconductor Science and Technology 17, 1023-1027 (2002)
In this paper we report on fluorescence-detected XAS measurements in arsenic-doped p-type indium selenide. Absorption spectra taken at the arsenic K-edge allow for an unambiguous determination of the bond length of the As atoms with their first neighbours that turns out to be 2.56 ± 0.02 Å. The XANES spectrum and the bond length (as determined from EXAFS oscillations) exhibit weak anisotropy as the angle between the crystal c-axis and the x-ray polarization vector is changed. These results are fully compatible with the model of a single substitutional acceptor (As in Se site), with no bonds along the c-axis (that would give rise to strong linear dicroism in the XANES spectrum). The In–As bond length is smaller than that found in compounds such as InAs. This reduction is coherent with the reduced number of first neighbour In atoms (in trigonal configuration) and the increased electrostatic attraction between the ionized acceptor and the In cations.