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High Efficiency Solar Cell Based on Full PVD Processed Cu(In,Ga)Se 2 /CdIn 2 S 4 Heterojunction
Author(s) -
Barreau Nicolas,
Frelon Agathe,
Lepetit Thomas,
Gautron Eric,
Gautier Nicolas,
RibeiroAndrade Rodrigo,
Nicoara Nicoleta,
Sadewasser Sascha,
Zabierowski Pawel,
Arzel Ludovic,
Choubrac Léo,
Harel Sylvie,
Deudon Catherine,
Latouche Camille,
Jobic Stéphane,
Caldes Maite,
Assmann Lionel,
Tsoulka Polyxeni,
Péan Emmanuel V.,
Lorthioir Justine,
Geschier Frédéric,
Braems Isabelle,
Moret Matthieu,
Briot Olivier,
Ouvrard Guy
Publication year - 2017
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201700140
Subject(s) - heterojunction , crystallite , solar cell , materials science , stoichiometry , thin film , quantum tunnelling , evaporation , transmission electron microscopy , optoelectronics , layer (electronics) , analytical chemistry (journal) , nanotechnology , chemistry , metallurgy , physics , organic chemistry , chromatography , thermodynamics
The original goal of our study is to synthesize by co‐evaporation the phase that could be formed at the interface between polycrystalline p‐Cu(In,Ga)Se 2 treated with KF and n‐CdS. Hence, a new buffer layer, CdIn 2 S 4 (C24), deposited by co‐evaporation is presented for the use in thin film solar cells, exhibiting device efficiencies as high as 16.2%, comparable to that obtained on a reference standard CdS‐buffered device. The physico‐chemical and optical properties of close to stoichiometry 400 nm‐thick films of C24 show similar properties to what has been reported in the literature for single crystals. The layer stack used for solar cells is investigated by transmission electron microscopy, showing the formation of an ultrathin Cd‐deficient C24 layer at the CIGSe/C24 interface, while a clear lattice match is observed at the C24/ZnO interface. Advanced electrical characterizations of the devices suggest that the output voltage and fill factor of the solar cells based on Cu(In,Ga)Se 2 /(PVD)C24 are limited by tunneling‐enhanced recombination through extended band tail states. These results open new routes to explain the superiority of wet processes used for the junction formation compared to vacuum‐based approaches.