ALD-ZnMgO and absorber surface modifications to substitute CdS buffer layers in co-evaporated CIGSe solar cells Ramis Hertwig, Shiro Nishiwaki, Mario Ochoa, Shih-Chi Yang, Thomas Feurer, Evgeniia Gilshtein, Ayodhya N. Tiwari and Romain Carron EPJ Photovolt., 11 (2020) 12 Published online: 25 January 2021 DOI: 10.1051/epjpv/2020010