Compound semiconductor structures for solar energy harvesting

Materials Colloquium 2020 - November, 4th, 16:30


Anna Fontcuberta i Morral (Laboratory of Semiconductor Materials, EPFL)

Solar energy harvesting constitutes of the technological paths to replace production of electrical power by burning fossil fuels. Some compound semiconductors such as GaAs and InGaAsP exhibit a high absorption coefficient in the photon energy of interest for solar energy conversion. Their commercial potential in terrestrial applications is reduced due to the scarcity (and thus high cost) of group III elements such as In and Ga. In this talk we present two approaches to render the use of this kind of materials sustainable: a strong reduction in material use through nanostructures and the replacement of group III by group II such as zinc. We find nanostructures also provide a path to increase light collection [1]. We show how II-V compounds such as Zn3P2 exhibit one magnitude higher absorption coefficient than GaAs [2]. We explain how these materials can be fabricated with high crystal quality, opening the path for the creation of alternative and sustainable compound semiconductor solar cells [3,4].

[1] P. Krogstrup et al Nature Photon 7, 306 (2013)
[2] M.Y. Swinkels et al Phys. Rev. Appl. 14, 024045 (2020)
[3] S. Escobar Steinvall et al Nanoscale Horizons 5, 274-282 (2020)
[4] R. Paul et al, Crys. Growth. Des. 20, 3816–3825 (2020)

Overview Materials Colloquium 2020