INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Electrodeposited Cu2ZnSnS4 thin films
Autor/es:
VALDES, MATÍAS; MODIBEDI, M; FRONTINI, MARÍA ALEJANDRA; VAZQUEZ, MARCELA; HILLIE, T
Lugar:
Pretoria
Reunión:
Congreso; 13th Topical Meeting of the International Society of Electrochemistr; 2013
Institución organizadora:
International Society of Electrochemistry
Resumen:
Electrodeposited Cu2ZnSnS4 thin films
M. Valdes1, M. Modibedi2, M.A. Frontini1, M. Vazquez1*, T. Hillie2
1División Electroquimica y Corrosión, INTEMA, UNMdP-CONICET
J. B. Justo 4302 B7608FDQ Mar del Plata, ARGENTINA
(*) mvazquez@fi.mdp.edu.ar
2 Energy and Processes, Materials Science and Manufacturing, CSIR, PO Box 395,
Pretoria, ZA0001, South Africa
3National Centre for Nano-structured Materials, CSIR, PO Box 395, Pretoria, ZA0001,
South Africa
Cu2ZnSnS4 (CZTS) is a quaternary semiconductor compound that has recently emerged
as one of the promising candidates for thin film photovoltaic devices. The advantages
involve its direct band gap (1.45-1.50 eV) and high absorption coefficient (above 104
cm−1). Besides, all the constitutive elements in CZTS are abundant and environmentally
friendly. Among the methods to produce CZTS thin films, electrochemical approaches
present important features: they are cost-effective (mainly because they do not require
high vacuum o high temperatures), they can be used in large and flexible substrates
(even in intricate geometries) and they can be scaled-up into industrial production.
In this work Cu2ZnSnS4 (CZTS) thin films have been prepared using Electrochemical
Atomic Layer Deposition (E-ALD) and compared to one-step conventional constant
potential electrodeposition. E-ALD is the electrochemical analog of atomic layer
deposition and it is based on the alternating underpotential deposition (UPD) of the
elements to form the compound semiconductor in a cycle. UPD is a surface limited
phenomenon; the resulting deposit is generally limited to an atomic layer. When the
UPD range is changed, the driving force is not sufficient to grow atoms on top of the
underlying atoms; thus, each deposition cycle can form only a monolayer of
heterogeneous elements, and the thickness of the deposit is controlled by the number of
deposition cycles.
Optimal deposition conditions were investigated using cyclic voltammetry (CV) on
TCO, Au and Au/S covered electrodes. Then, based on CVs results, CZTS films were
growth employing different E-ALD deposition cycles like Au/S/Cu/S/Zn/S/Sn/S to
form the desired quaternary compound. The results were compared to those of
conventional one-step electrodeposition performed at -1.1 V vs. Ag/AgCl during 1
hour. Other deposition parameters were also investigated in an attempt to optimize the
stoichiometry.
The crystal structure of the films was characterized by XRD and micro Raman
spectroscopy, while the morphology, thickness, topography and elemental composition
were addressed using FI-SEM, AFM and EDS.