Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 18: Optical Analysis of Thin Films (Reflection, Ellipsometry, Raman, IR-DUV Spectroscopy, ...): Session I

DS 18.9: Vortrag

Mittwoch, 14. März 2018, 12:15–12:30, H 0111

Electroreflectance and photoluminescence of Cu2(Zn1-x,Cdx)SnS4 thin film solar cells — •Segiu Levcenco¹, Shreyash Hadke², Lydia Helena Wong², and Thomas Unold¹ — ¹Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin, Germany — ²Energy Research Institute @ NTU Nanyang Technological University 637553, Singapore

Although Cu2(Zn1-x,Cdx)SnS4 (CZCTS)- absorber layers have demonstrated efficiency of 11.5% in thin film solar cells devices their optical and defect properties are not investigated sufficiently. For instance, the band gap in these materials is often derived from the external quantum efficiency measurements and different reports have provided band gaps that vary for similar compositions of CZCTS. In this work we employ the electroreflectance (ER) and photoluminescence (PL) techniques for characterizing CZCTS devices. The effects of Cd content and Cu/(Zn+Sn) cations ratio on the electronic transitions are investigated. In the near band edge region the ER spectra provide distinct derivative like structures corresponding to transitions near the critical points of the dielectric function, which are used to evaluate the band gap transition energies. In addition, a defect recombination with transition energy in the range of 1.1-1.3 eV has been resolved in PL spectra.