Role of transition metals and rare-earth elements in preparation of InP-based materials for radiation detectors.

The project proposal focuses on the study of the influence of rare-earth elements (RE) on the bulk crystals of InP prepared by the Czochralski method and on epitaxial layers prepared by LPE in order to getter unintentional impurities. Diminished concentrations of unintentional impurities in bulk crystals allow to lower concentrations of transition metals (TM) which are necessary to reach the SI state. Besides commonly used Fe, we will prepare high-quality SI material by alternative TM (Ti, Cr) doping, and we will investigate the thermal stability and redistribution of the TM and RE dopants in the substrate and adjacent p-type layer. To improve the metal/InP interface, the electrophoretic deposition of nanosized metal particles will be employed. Prepared structures will be characterized by electrical, optical, and microscopic techniques: Hall-effect measurements, DLTS, AS, photoluminescence, SEM, AFM, and SIMS.