Descrição
In this work, we investigated structural, morphological, electrical, and optical properties from a set of
Cu2ZnSnS4 thin films grown by sulfurization of metallic precursors deposited on soda lime glass substrates
coated with or without molybdenum. X-ray diffraction and Raman spectroscopy measurements revealed the
formation of single-phase Cu2ZnSnS4 thin films. A good crystallinity and grain compactness of the film was
found by scanning electron microscopy. The grown films are poor in copper and rich in zinc, which is a
composition close to that of the Cu2ZnSnS4 solar cells with best reported efficiency. Electrical conductivity and
Hall effect measurements showed a high doping level and a strong compensation. The temperature dependence
of the free hole concentration showed that the films are nondegenerate. Photoluminescence spectroscopy showed
an asymmetric broadband emission. The experimental behavior with increasing excitation power or temperature
cannot be explained by donor-acceptor pair transitions. A model of radiative recombination of an electron with
a hole bound to an acceptor level, broadened by potential fluctuations of the valence-band edge, was proposed.
An ionization energy for the acceptor level in the range 29–40 meV was estimated, and a value of 172 ±2 meV
was obtained for the potential fluctuation in the valence-band edge.
; Santos, N. M. 
