Electronic Conduction Mechanisms and Defects in Polycrystalline Antimony Selenide

Abstract

A study on the electronic conduction mechanisms and electrically active defects in polycrystalline Sb2Se3 is presented. It is shown that, for temperatures above 200 K the electrical transport is dominated by thermal emission of free holes, ionized from shallow acceptors, over the inter-grain potential barriers. The temperature dependence of the holes mobility, limited by the inter-grain potential barriers, is the main contributor to the observed conductivity thermal activation energy. At lower temperatures, nearest-neigbour and Mott variable range hopping transport in the bulk of the grains are the dominant conduction mechanisms. Based on this study, the important parameters of the electronic structure of the Sb2Se3 thin-film such as free hole density and mobility, inter-grain potential barrier height, intergrain trap density, shallow acceptor ionization energy, acceptor density, net donor density 2 and compensation ratio are reported. ; P. M. P. Salomé acknowledges the funding of Fundacão para Ciência e Tecnologia (FCT) through the project IF/00133/2015. This research is supported by Development of novel ultrathin solar cell architectures for low-light, low-cost and flexible opto-electronic devices project (028075) co-funded by FCT and ERDF through COMPETE2020. B. Vermang has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement n 715027). A. Shongalova acknowledges the funding of Erasmus + program 2016/17. This work was funded by FEDER funds through the COMPETE 2020 Programme and by FCT -Portuguese Foundation for Science and Technology under the projects UID/CTM/50025/2013. The financial support from Brazilian funding agencies CNPq, CAPES and FAPEMIG is also acknowledged.