The deposition of thin films of cadmium zinc sulfide Cd1−x Zn x S at 250 °C from spin-coated xanthato complexes: a potential route to window layers for photovoltaic cells

Abstract

Thin films of Cd 1-x Zn x S (CZS) were prepared by a novel spin coating/melt method from cadmium ethylxanthato [Cd(C 2 H 5 OCS 2 ) 2 ] and zinc ethylxanthato [Zn(C 2 H 5 OCS 2 ) 2 ] in x ratios of 0-0.15 and of 1. A solution of the precursor(s) in THF was spin coated onto a glass substrate and then heated at 250°C for 1 h under N 2 . The thickness of the film formed can be controlled by varying the solution composition and/or the spin rate of the coating. A total metal precursor solution concentration of 50 mM was used in all cases. The films were characterized by p-XRD, SEM, EDX, ICP-AES, XPS, UV-Vis absorption spectroscopy, Raman spectroscopy and resistivity measurements. The band gaps of the films were between 2.35-2.58 and 3.75 eV (0 B x B 0.15 and at x = 1). The resistivity of Cd 1-x Zn x S films was found to vary linearly with zinc contents, and the properties of the films suggest potential application to photovoltaics as window layers. This work is the first study to demonstrate Cd 1-x Zn x S thin films by a spin coating/melt method from xanthato precursors.

Synthesis and characterization of zinc di(O-2,2-dimethylpentan-3-yl dithiocarbonates) bearing pyridine or tetramethylethylenediamine coligands and investigation of their thermal conversion mechanisms towards nanocrystalline zinc sulfide

“…44,45 Additionally, by mixing different ratios of metal xanthates, doped metal sulfides with various transition metals can be resulted and several studies showed that such systems are very useful for controlling the optical, electrical and crystalline properties. [46][47][48] The metal xanthates are generally stable at room temperature and their decomposition typically occurs thermally via a mechanism known as Chugaev elimination. 24 However, it is also possible to decompose them chemically with the use of primary amines at room temperature 49 as well as photochemically with UV irradiation.…”

Synthesis, X-ray Single-Crystal Structural Characterization, and Thermal Analysis of Bis(O-alkylxanthato)Cd(II) and Bis(O-alkylxanthato)Zn(II) Complexes Used as Precursors for Cadmium and Zinc Sulfide Thin Films

“…All syntheses of the ligands ( 1 – 6 ) and precursors ( 7 – 20 ) were performed under dry N 2 , using standard Schlenk techniques. The ligands ( 1 – 6 ) and precursors ( 7 – 20 ) were prepared as described in the literature. , The tuning of surface morphology of thin film nanostructures is an essential step in optimization of solar cell layers and has a strong influence on the optical properties of the films . Toward this end, the impact precursor structure has on the film microstructure/nanostructures has been widely reported. − Full synthetic methods, elemental analysis, NMR data, and other characterization of ligands and precursors are described in SI.…”

“…Alkylxanthato cadmium and zinc complexes have been used as single source molecular precursors toward thin films of cadmium sulfide (CdS) and zinc sulfide (ZnS), respectively. − CdS is a II–VI compound semiconductor with a wide direct band gap (2.4 eV), making it useful in a variety of electronic and photovoltaic applications . CdS crystallizes in both hexagonal (wurtzite) and cubic (zinc blende) polymorphs.…”

“…The successful synthesis of face-centered cubic CdS nanoparticles was reported by Wang and coauthors through a synthetic process of liquid–solid-solution phase transfer and separation. ZnS is another II–VI semiconductor with an even wider direct band gap of 3.7 eV . ZnS exists as hexagonal wurtzite or cubic zinc blende polymprphs.…”

Structural, surface morphological, optical and thermoelectric properties of sol–gel spin coated Zn doped CdS thin films

“…Different techniques such as chemical bath deposition [7], vacuum evaporation [8], spray pyrolysis [9], spin coating [10], sputtering [11], chemical vapour deposition [12], molecular beam epitaxy [13], sol-gel [14], successive ionic layer and reaction (SILAR) [15] have been performed for the synthesis of Zn doped CdS nanostructured thin films. Among these methods, the sol-gel spin coating technique had an advantage like low cost with simple working principle, easy compositional modifications and its ability to quickly produce very uniform thin films ranging from few nanometres to microns in thickness low annealing temperature and large growth area of the film [16].…”