INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Spray deposition of Cu2ZnSnS4 thin films
Autor/es:
M. VALDÉS; G. SANTORO; M. VÁZQUEZ
Lugar:
Joao Pessoa
Reunión:
Congreso; VIII Congreso de la Sociedade Brasileira de Pesquisa em Materiais (SBPMat); 2014
Institución organizadora:
Sociedade Brasileira de Pesquisa em Materiais (SBPMat)
Resumen:
Cu2ZnSnS4 (CZTS) is an
excellent candidate dor the absorbing layer in photovoltaic devices [1]. It has excellent optical properties (a ~105 cm-1) and a band gap matching the solar spectrum
(1.4£ Eg£1.5 eV). Also, it does not contain toxic or scarce elements.
Spray pyrolysis has
been used before to deposit thin films [2]. It is cost effective, does not
require high vacuum, can copy irregular geometries and suitable for flexible
substrates.
Thin films of CZTS have been deposited on glass
and on conductive glass (FTO) using spraying aqueous precursors. Temperatures
ranged from 325 to 425 ºC. The effect of annealing in sulfur vapor on the
structural, morphological, and optical properties of CZTS films has been
studied. XRD revealed the formation of polycrystalline CZTS films, where the
crystalline degree increased with substrate temperature and with sulfurization.
Raman maps show a homogenous distribution of the CZTS phase and a random
distribution of a CuXS binary phase. Raman signals attributed to
this secondary phase seem to be reduced after sulfurization. Band gap values
vary between 1.3 and 1.5 eV. Sulfurization has no significant effect on the
composition of the deposits or on the band gap energy. The crystallite size
increased after annealing in sulfur. Films deposited at 425 ºC presented a
nearly stoichiometric composition, suitable optical properties and p-type
conductivity. CZTS is suitable for absorbent layers in solar cells, even in the
as-deposited condition [3].