Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 27: Photovoltaics: Innovative Material Systems

HL 27.4: Talk

Tuesday, March 27, 2012, 10:15–10:30, ER 270

Radiative recombination in kesterite Cu2ZnSnS4 single crystals — •Sergej Levcenko¹, Viktor Tezlevan¹, Ernest Arushanov¹, Susan Schorr², and Thomas Unold² — ¹Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, MD 2028, Moldova — ²Helmholtz Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany

Among the quaternary chalcogenides, Cu2ZnSnS4 (CZTS) semiconductor has attracted much attention due to their potential photovoltaic application. A recent record conversion efficiency value of 8.2% has been achieved on CZTS-solar cell devices [1]. Although there are a number of studies discussing the development of thin film CZTS based solar cells, there are only a few reports concerning the basic material properties of CZTS. Here, we report a detailed study on the emission properties of the CZTS single crystals by photoluminescence (PL) spectroscopy. CZTS single crystals were grown by chemical vapor transport technique using iodine as a transport agent. At low temperature the PL spectrum shows one broad asymmetric band peaked at around 1.29 eV. Temperature and excitation intensities dependences of the PL band indicate that it is due to a free to bound recombination type recombination mechanism that involves a free electron and a trapped hole in the acceptor state with an activation energy of 150 meV. We attribute this acceptor level to Cu on Zn antisite defects.

[1] B. Schin, O. Gunawan, Y. Zhu, N.A. Bojarczuk, S. J. Chey, S. Guha, Prog. Photovolt: Res. Appl. (2011).