Films cadmium sulfide

Power GP, Peggs DR, Parker AJ (1981) The Cathodic formation of photoactive cadmium sulfide films from thiosulfate solutions. Electrochim Acta 26 681-682... 

Baranski AS, Fawcett WR, McDonald AC, Nobriga RM, McDonald JR (1981) The structural characterization of cadmium sulfide films grown by cathodic electrodeposition. J Electrochem Soc 129 963-968... 

Rieke PC, Bentjen SB (1992) Deposition of cadmium sulfide films by decomposition of thiourea in basic solutions. Chem Mater 5 43-53... 

The concentrations depend on the solution composition, for instance cadmium sulfide films prepared at lower pH are close to stoichiometry whereas those prepared at higher pH have a ratio [Cd]/[S] about 1.1 due to the presence of hydroxide species (Cd(OH)2) [45]. The formation of other hydroxy-sulfide films (ofZn [105,106], In [116], Sn [116]) can be also related to competitive precipitation phenomenon. As a consequence, the analysis of the solubility diagrams of all solid compounds in a given CBD system is a useful tool to improve the composition control of the films. This approach... 

Fatas, E., et al.. Morphology and properties of electrodeposited cadmium sulfide films in nonaqueous solvents. Mater. Chem. Phys., 1985.13 p. 497-502. 

Peter, L.M., The electrocrystallization of cadmium sulfide films on cadmium. 

Yeh, L.S.R., P.G. Hudson, and A. Damjanovic, Anodic formation of thin cadmium sulfide films. 1. Kinetics and mechanisms under galvanostatic and potentiodynamic conditions. J. Appl. Electrochem., 1982. 12 p. 153-62. 

Similar studies were done for cadmium sulfide films by Power, et al. (54). The films were cathodicaily deposited according to the reaction ... 

Iron oxide films were deposited from millimolar Fe(N03)3 solutions adjusted to a pH of 2.0 to 4.0 with nitric acid. Hydrolysis and condensation was induced by heating to 90 C with stirring. Cadmium sulfide films were prepared from O.IM cadmium nitrate and l.OM ammonium nitrate solutions at pH vdues ranging from 8.5 to 10.5. Sulfide was generated in-situ by base decomposition of thiourea at 0.05M concentration. The films were removed from solution at various time intervals up to the point at which a massive precipitate became visible in the bulk of solution. 

Cadmium sulfide films were deposited on substrates in basic cadmium nitrate solutions with cadmium complexed by excess ammonia. Slow decomposition of thiourea was used to generate the sulfide ion. Some initial studies of film growth on derivatized polyethylene suggested a dependence of film density surface on... 

Figure 7. Electron micrographs of cadmium sulfide films deposited on a hydrophilic silicon substrate and on a hydrophobic SAM substrate at various times after initiation of film deposition.

Cadmium Sulfide Photoconductor. CdS photoconductive films are prepared by both evaporation of bulk CdS and settHng of fine CdS powder from aqueous or organic suspension foUowed by sintering (60,61). The evaporated CdS is deposited to a thickness from 100 to 600 nm on ceramic substates. The evaporated films are polycrystaUine and are heated to 250°C in oxygen at low pressure to increase photosensitivity. Copper or silver may be diffused into the films to lower the resistivity and reduce contact rectification and noise. The copper acceptor energy level is within 0.1 eV of the valence band edge. Sulfide vacancies produce donor levels and cadmium vacancies produce deep acceptor levels. 

Copper Sulfide—Cadmium Sulfide. This thin-film solar cell was used in early aerospace experiments dating back to 1955. The Cu S band gap is ca 1.2 eV. Various methods of fabricating thin-film solar cells from Cu S/CdS materials exist. The most common method is based on a simple process of serially overcoating a metal substrate, eg, copper (16). The substrate first is coated with zinc which serves as an ohmic contact between the copper and a 30-p.m thick, vapor-deposited layer of polycrystaUine CdS. A layer is then formed on the CdS base by dipping the unit into hot cuprous chloride, followed by heat-treating it in air. A heterojunction then exists between the CdS and Cu S layers. 

MiUer B, Menezes S, Heller A (1978) Anodic formation of semiconductive sulfide films at cadmium and bismuth Rotating ring-disk electrode studies. 1 Electroanal Chem 94 85-97... 

Lincot D, Ortega-Borges R (1992) Chemical bath deposition of cadmium sulfide thin films. In situ growth and structural studies by Combined Quartz Crystal Microbalance and Electrochemical Impedance techniques. J Electrochem Soc 139 1880-1889... 

Ortega-Borges R, Lincot D (1993) Mechanism of chemical bath deposition of cadmium sulfide thin films in the ammonia-thiourea system. J Electrochem Soc 140 3464-3473... 

Xi D, Zhang H, Furst S, Chen B, Pei Q (2008) Electrochemical synthesis and photovoltaic property of cadmium sulfide-polybithiophene interdigitated nanohybrid thin films. J Phys ChemC 112 19765-69... 

Let us add here that the fabrication of polycrystalline semiconductive films with enhanced photoresponse and increased resistance to electrochemical corrosion has been attempted by introducing semiconductor particles of colloidal dimensions to bulk deposited films, following the well-developed practice of producing composite metal and alloy deposits with improved thermal, mechanical, or anti-corrosion properties. Eor instance, it has been reported that colloidal cadmium sulfide [105] or mercuric sulfide [106] inclusions significanfly improve photoactivity and corrosion resistance of electrodeposited cadmium selenide. 

Mau AWH, Huang CB, Kakuta N, Bard AJ, Campion A, Eox MA, White JM, Webber SE (1984) Hydrogen photoproduction by Nafion/cadmium sulfide/platinum films in water/sulfide ion solutions. J Am Chem Soc 106 6537-6542... 

A prime contender for leading thin film technology as applied to solar cells is cadmium telluride (CdTe). Its bandgap is almost ideal for use as a solar cell for energy conversion from the Sun s spectrum. Here, CdTe and cadmium sulfide (CdS) are used to produce a low cost thin film solar cell... 

Meth, J. S. Zane, S. G. Sharp, K. G. Agrawal, S. 2003. Patterned thin film transistors incorporating chemical bath deposited cadmium sulfide as the active layer. Thin Solid Films. 444 227-234. 

The CBD CdS was also applied in other areas of device fabrication and application. Mereu et al.32 fabricated thin-film field-effect transistors using CBD CdS on Si02/Si (n-type) substrates. Meth et al.33 fabricated thin-film transistors (TFTs) that incorporated patterned CBD cadmium sulfide as the active layer. Mobility in the =1 -cm2/Vs range with on/off ratios of =105 are needed for practical TFTs (e.g., for displays). Mobility values of 0.1 -1 cm2/Vs with on/off ratios exceeding 107 have been reported for these types of TFTs using CBD CdS. 

Kitaev, G. A. Uritskaya,A. A. Moksushin, S. G. 1965. Conditions for the chemical deposition of thin films of cadmium sulfide on a solid surface. Russ. J. Phys. Chem. 39 1101-1102. 

Popescu, V. Pica, E. M. Pop, I. Grecu, R. 1999. Optical properties of cadmium sulfide thin films, chemically deposited from baths containing surfactants. Thin... 

O Brien, R McAleese, J. 1998. Deposition and characterization of cadmium sulfide thin films by chemical bath deposition. /. Mater. Chem. 8 2309-2314. 

The first deposition experiments using SILAR were performed to grow zinc and cadmium chalcogenide films.1 Metal salt solutions and sodium sulfide were used as precursors in most experiments. Table 8.2 provides a more complete... 

Nicolau, Y. F. Menard, J. C. 1990. Procedure for solution growth of zinc sulfide, cadmium sulfide, and zinc cadmium sulfide (Zn xCdxS) thin films by successive ionic-layer adsorptions and reactions. J. Appl. Electrochem. 20 1063-1066. 

The electrodeposition of cadmium sulfide thin films was carried out by the electroreduction of the aqueous thiocyanate complex of Cd(II). Formation of CdS is supposed to proceed by metal-catalyzed ligand reduction [179]. 

To date, cadmium sulfide, zinc sulfide, lead sulfide, cadmium selenide, and lead selenide semiconductor particulate films have been grown, in situ, under... 

Cadmium sulfide particulate films, generated in thicknesses of 300 50 A at arachidic acid (AA) monolayer interfaces, have been characterized in situ by STM under potentiostatic control [644], Electrical contact was made between the tip of the STM, acting as the working electrode (WE), which was in contact with the CdS particulate film floating on aqueous 0.30 M NaCl, and the reference (RE) and counter (CE) electrodes, placed in the subphase (Fig. 112) [644]. A well-defined single-reduction wave at about — 1.15 V was observed. Prolonged exposure to room light shifted the reduction peak to — 0.85 V. Electrical and photoelectrical characterizations have also been performed on Ti-foil-supported, 5000-A-thick CdS particulate films in an electrochemical cell (Fig. 113) [644]. The Ti foil was used as the WE, while the RE and CE were placed into 0.50 M... 

Sol-gel techniques can be used to produce thin layers, as described in Section 19.1. For example, cadmium sulfide layers for photocells are easily made by spraying an ammoniacal solution of cadmium chloride and thiourea (which hydrolyzes to give sulfide ion) onto a substrate surface and baking the resulting CdS film at up to 500 °C ... 

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