Investigation of the local structure of As-related acceptor centres in InSe by means of fluorescence-detected XAS

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 A. 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 bo…