Materials Chemistry and Physics, Vol.172, 165-172, 2016
Single crystal growth and electronic structure of TlPbI3
High-quality inclusion-free TlPbI3 single crystals have been grown using Bridgman-Stockbarger method. The electronic structure of TlPbI3 is studied by using the possibilities of X-ray photoelectron spectroscopy (XPS). For the TlPbI3 crystal, XPS core-level and valence-band spectra for both pristine and Ar+ ion-bombarded surfaces are recorded. The present XPS data indicate that the TlPbI3 single crystal surface is somewhat sensitive with respect to Ar+ ion-bombardment. In particular, the XPS measurements reveal that thallium and lead atoms are in the formal valence +1 and +2, respectively, on the pristine TlPbI3 single crystal surface. Further, the 3.0 keV Ar+ ion-bombardment of the surface induces partial transformation of lead ions to lower valence state, namely Pb; however, no partial loss of iodine atoms belonging to TlI8 polyhedra occurs due to the Ar+ ion-bombardment of the TlPbI3 surface because after such a treatment thallium remains exclusively in the formal valence +1. The present XPS results indicate that low hygroscopicity is characteristic of the TlPbI3 single crystal surface. Photoinduced birefringence profiles in TlPbI3 are explored. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Optical materials;Semiconductors;Crystal growth;Photoelectron spectroscopy;Electronic structure