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Muonium states in Cu 2 ZnSnS 4 solar cell material

2014; IOP Publishing; Volume: 551; Linguagem: Inglês

10.1088/1742-6596/551/1/012045

1742-6596

H. V. Alberto, R. C. Vilão, J. M. Gil, J. Piroto Duarte, Ricardo Vieira, A. Weidinger, Joaquim P. Leitão, A.F. da Cunha, M.G. Sousa, Jennifer P. Teixeira, Paulo A. Fernandes, P.M.P. Salomé, Kristi Timmo, Mihkel Loorits, A. Amato, H. Luetkens, T. Prokscha, A. Suter, Z. Salman,

Copper-based nanomaterials and applications

We investigated bulk and thin-film samples of the quaternary p-type semiconductor Cu2ZnSnS4 (CZTS) by μSR, in order to characterize the existing muonium signals. We find that the majority of the implanted muons form a diamagnetic state broadened by an interaction with the Cu nuclear moments, which we interpret as Mu+ bound to sulphur. A paramagnetic fraction is also present at low temperatures and the ratio between the two muon charge states, Mu+ and Mu0, varies between 20 and 40% prior to the onset of muon diffusion, which occurs at around 150 K. The fraction of Mu0 is found to be sensitive to the defect content of the sample. The paramagnetic fraction has two different contributions and their origin is discussed and related with the muon role as a probe for charge carriers in the material.