Thermochemical and kinetic aspects of the sulfurization of Cu-Sb and Cu-Bi thin films

Journal Article · Wed Feb 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.11.025· OSTI ID:21612887

Colombara, Diego ^[1]; Peter, Laurence M ^[1]; Rogers, Keith D; Hutchings, Kyle ^[2]

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1. Department of Chemistry, University of Bath, Bath BA2 7AY (United Kingdom)
2. Centre for Materials Science and Engineering, Cranfield University, Shrivenham, SN6 8LA (United Kingdom)

CuSbS{sub 2} and Cu{sub 3}BiS{sub 3} are being investigated as part of a search for new absorber materials for photovoltaic devices. Thin films of these chalcogenides were produced by conversion of stacked and co-electroplated metal precursor layers in the presence of elemental sulfur vapour. Ex-situ XRD and SEM/EDS analyses of the processed samples were employed to study the reaction sequence with the aim of achieving compact layer morphologies. A new 'Time-Temperature-Reaction' (TTR) diagram and modified Pilling-Bedworth coefficients have been introduced for the description and interpretation of the reaction kinetics. For equal processing times, the minimum temperature required for CuSbS{sub 2} to appear is substantially lower than for Cu{sub 3}BiS{sub 3}, suggesting that interdiffusion across the interfaces between the binary sulfides is a key step in the formation of the ternary compounds. The effects of the heating rate and sulfur partial pressure on the phase evolution as well as the potential losses of Sb and Bi during the processes have been investigated experimentally and the results related to the equilibrium pressure diagrams obtained via thermochemical computation. - Graphical Abstract: Example of 3D plot showing the equilibrium pressure surfaces of species potentially escaping from chalcogenide films as a function of temperature and sulfur partial pressure. Bi{sub (g)}, Bi{sub 2(g)}, and BiS{sub (g)} are the gaseous species in equilibrium with solid Bi{sub 2}S{sub 3(s)} considered in this specific example. The pressure threshold plane corresponds to the pressure limit above which the elemental losses from 1 {mu}m thick films exceeds 10% of the original content per cm{sup 2} area of film and dm{sup 3} capacity of sulfurization furnace under static atmosphere conditions. The sulfurization temperature/sulfur partial pressure boundaries required to minimise the elemental losses below a given value can be easily read from the 2D projection of the intersection curves into the T-p{sub S2} plane. Highlights: Black-Right-Pointing-Triangle Sulfurization of Sb-Cu and Bi-Cu metal precursors for thin film PV applications. Black-Right-Pointing-Triangle Kinetics shows the rate determining step to be the interdiffusion of binary sulfides. Black-Right-Pointing-Triangle Phase evolution is consistent with Pilling-Bedworth coefficients of Cu, Sb and Bi. Black-Right-Pointing-Triangle Elemental losses can be minimised via the use of equilibrium pressure diagrams.

• OSTI ID: 21612887
• Journal Information: Journal of Solid State Chemistry, Vol. 186; Other Information: DOI: 10.1016/j.jssc.2011.11.025; PII: S0022-4596(11)00631-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCULATION METHODS
DIAGRAMS
HYDROGEN SULFIDES
INTERFACES
LAYERS
MORPHOLOGY
PARTIAL PRESSURE
PHOTOVOLTAIC EFFECT
REACTION KINETICS
SCANNING ELECTRON MICROSCOPY
SOLIDS
SULFUR
SURFACES
TEMPERATURE DEPENDENCE
THIN FILMS
X-RAY DIFFRACTION
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
FILMS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
MICROSCOPY
NONMETALS
PHOTOELECTRIC EFFECT
PHYSICAL PROPERTIES
SCATTERING
SULFIDES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES