In the last decade, transparent amorphous oxide semiconductors (TAOS) have become an essential component of many electronics, from ultra high resolution displays to solar cells. However, these disordered oxides typically rely on expensive component metals like indium to provide sufficient charge carrier conduction, and their optoelectronic properties are not as predictable and well-described as those of traditional, crystalline semiconductors. Herein we report on our comprehensive study of the amorphous zinc-tin-oxide (a-ZTO) system for use as an indium-free, n-type TAOS. Using a combination of high-throughput co-deposition growth, high resolution spectral mapping, and atomistic calculations, we explain the development of disorder-related subgap states in SnO 2 -like a-ZTO and optical bandgap reduction in ZnO-like a-ZTO. In addition, we report on a composition-induced electronic and structural transition in ZnO-like a-ZTO resulting in an exceptionally high figure of merit, comparable to that of amorphous indium-gallium-zinc-oxide. Our results accelerate the development of a-ZTO and similar systems as indium-free TAOS materials.
Bibliographical noteFunding Information:
Use of the National Synchrotron Light Source at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886. This material is based upon the work supported by the Air Force Office of Scientific Research under Award No. FA9550-18-1-0024. This research has received funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 641864 (INREP). This work made use of the ARCHER UK National Supercomputing Service (hhtp://www.archer.ac.uk) via the membership of the UK’s HPC Materials Chemistry Consortium, funded by EPSRC (Grant No. EP/L000202) and the Balena HPC facility of the University of Bath. B.J.M. acknowledges support from the Royal Society (Grant No. UF130329). Z.W.L.-H. was supported by a scholarship from the Summer Scholars and Artists Program at Binghamton University.
© 2018 Author(s).