Photoinduced current transient spectroscopy technique applied to the study of point defects in polycrystalline CdS thin films

Akkad, F. El; Ashour, H.

doi:10.1063/1.3117510

Cited by 7 publications

(3 citation statements)

References 29 publications

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“…There have been many CdS deposition techniques including vacuum evaporation (Grynko et al, 2009), RF sputtering (Akkad and Ashour, 2009), chemical vapor deposition (Jones et al, 2009) and molecular beam epitaxy (Ueta et al, 2000). All these methods require special tools, and therefore their manufacturing cost is high.…”

Section: Introductionmentioning

confidence: 99%

Growth of CdS thin films and nanowires for flexible photoelectrochemical cells

Sankır

Doğan

2011

Journal of Materials Processing Technology

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Section: Introductionmentioning

confidence: 99%

Growth of CdS thin films and nanowires for flexible photoelectrochemical cells

Sankır

Doğan

2011

Journal of Materials Processing Technology

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“…The electrical conductivity and mobility of polycrystalline CdS thin films (prepared by spray pyrolysis) at dark and under illumination were performed to correlate with thicknesses. 12 Point defects play a vital role in this case.…”

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confidence: 98%

Sub-THz thermally activated-electrical conductivity of CdS thin films

Rahman

Scales

2016

Applied Physics Letters

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The electrical conductivity of a CdS thin film, controlled by grain structures is essential to enhance its photoconductivity to be able to be fit as a window material in CdS/CdTe heterojunction solar cell. In order to characterize a thin film, electromagnetically, we employed an open cavity resonator with a sub-millimeter VNA (Vector Network Analyzer). Our technique is capable of measuring complex dielectric permittivity,ǫ, of a photovoltaic film as thin as 0.1 µm. We measured the real part of the complex dielectric permittivity, ǫ re , and electrical conductivity, σ re (derived from the imaginary part, ǫ im ), of unannealed and annealed CdS films with thicknesses ∼ 0.15 µm on ∼ 3 mm thick-borosillicate glass substrates, at room temperature. We obtain the (thermally activated) electrical conductivity between 100 and 312 GHz, which is less in annealed samples than in unannealed one by ∼ 2 orders of magnitude. Contrary to our expectations, the carrier concentrations extracted from these data by fitting a Drude model, are ∼ 10 16 cm −3 (unannealed) and ∼ 10 14 cm −3 (annealed). We investigate the connection between grain size and carrier concentration.Cadmium sulphide (CdS) is an integral component of CdTe/CdS heterostructured-thin solar cell where it is used as a window material for its better photoconductivity, optolelectronic properties, and flexibilty.1-3 Its photoconductivity sensitivity depends on its electronic properties. CdS is usually layered with cadmium telluride (CdTe) to make efficient solar cells.4,5 Cadmium sulphide (CdS) contains many intrinsic defect-states which affect its electronic conductivity profile. The grain structure can also plays a role. The microstructures of polycrystalline materials are composed of different orientedgrains.6,7 The grain boundaries are characterized by a potential barriers. The photoexcitation can impact transport through these grain boundaries by various mechanisms. The electrical conductivity is the key property in all these phenomena. This photovoltaic material can be grown with many different techniques, and dielectric properties are growth-technique dependent.The annealing-effects (in vacuum and under argon atmosphere) on the electrical and optical conductivity of CdS (deposited by chemical bath deposition method) have been studied in the temperature range 200-400 K. In the article by Oumous and Hadiri 8 , for temperatures > 300 K, the conduction is explained by the traps at the grain boundaries for grains partially depleted. On the other hand, for temperatures < 300 K, the conduction results from a hopping due to localized states.In order to evaluate the quality of materials used in CdS/CdTe photovoltaic heterojunctions, the complex dielectric properties of polycrystalline CdS, formed into a thin film by sputter-deposition onto Silicon (Si) wafers, were investigated by in situ spectroscopic ellipsometry. 9The authors focused on understanding the excited carriers by fitting their data to carrier scattering model. This is in optical frequency range (0.75 to 6.5 eV...

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“…Dark and photoresistances of 400 nm thick CdS films deposited using RF magnetron sputtering was approximately 1x10 5 and 3x10 4 Ω/sq, respectively 3 . Electrical conductivity of RF magnetron sputtered CdS films as a function of film thickness and temperature, and the conductivity was controlled by a thermally activated mobility in the presence of an intergrain barrier 4 . Photoconductance in polycrystalline CdS films using conductance atomic force microscopy and found that photoconductivity along the grain boundaries was excited at photon energies significantly smaller than the band gap of CdS, whereas phototransport through the grains was detected only for photon energies above band gap 5 .…”

Section: Introductionmentioning

confidence: 99%

Untitled

2017

jusps-B

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Cd2+ rich Cadmium Sulfide (CdS) nanoperticles caped with Triethanolamine (TEA) as an organic ligand were synthesized by chemical precipitation. These nanostructured CdS nanoparticles were deposited on aluminum foil by electrophoretic deposition technique. Both nanoparticles and thin film are studied by x-ray diffraction, glancing incidence x-ray diffraction and atomic force microscopy measurements to understand the growth, stability and surface morphology. The highest photocurrent obtained as 6.5 µA at incident wavelength λ = 400 nm with an applied bias voltage of 10 V in the CdS thin films. Also time response of the photocurrent reveals the corrosion at the surface of CdS particles i.e get decompose into Cd 2+ and S 2-ions.

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Photoinduced current transient spectroscopy technique applied to the study of point defects in polycrystalline CdS thin films

Cited by 7 publications

References 29 publications

Growth of CdS thin films and nanowires for flexible photoelectrochemical cells

Growth of CdS thin films and nanowires for flexible photoelectrochemical cells

Sub-THz thermally activated-electrical conductivity of CdS thin films

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