Authors: Sanchez-Palencia, P; Garcia, G; Conesa, JC; Wahnon, P; Palacios, P

Article.
Acta Mater.. vol: 197. page: 1359-6454.
Date: sep-15. 2020.
Doi: 10.1016/j.actamat.2020.07.034.

Abstract:
Ternary spinel nitrides are a new class of semiconductor materials with tunable bandgap in the visible range. In this work, we report a rational design of spinel-type nitride compounds with improved features as solar cell absorber materials by way of the in-gap-band (IGB) concept. For this purpose, a systematic screening on the effect of transition metal (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo) hyper -doping on the crystal and electronic structure properties of germanium (Ge) and tin (Sn) spinel nitrides (gamma-(MmSnx-mGe1-x)(3)N-4, x = 0.5, m = 0.042, 0.083) was carried out through accurate ab-initio methods. The analysis of the electronic structure reveals that M-hyperdoped ternary spinel nitrides with M = Cr, Co, Cu show an IGB with the adequate properties to allow two extra photon absorption processes. A detailed study of the sunlight absorption properties, and maximum photovoltaic efficiencies reveal that Co-hyperdoped spinel is an excellent candidate to be used in photovoltaic devices as absorber material, with maximum photovoltaic efficiency of similar to 55%. Overall, our results suggest that it would be possible to design new ternary spinel-type nitride materials with improved absorption properties suitable for poten-tial use in photovoltaic applications. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved..