Optical Properties of Cadmium Oxide (CdO) Thin Films

<p>Cadmium (Cd) is a soft, silver-white or blue lustrous metal typically found in mineral deposits with lead, zinc and copper. Cadmium Oxide thin films have been prepared on a glass substrate at 350<sup>0</sup>C temperature by implementing the Spray Pyrolysis method. The direct and indirect band gap energies are determined using spectral data. The direct and indirect band gap energies decrease with the increasing film thickness. It is noted that for the same film thickness the direct band gap energy is greater than indirect band gap energy. The transmittance increases with the increasing wavelength for annealed and deposited films. It is also noted that for the same wavelength the transmittance for deposited films is greater than the transmittance for annealed films.</p>

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Optical and Electrical Characteristics of CdO thin films deposited by Spray Pyrolysis Method

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v32i1.2447 ◽

1970 ◽

Vol 32 (1) ◽

pp. 97-105 ◽

Cited By ~ 2

Author(s):

MM Islam ◽

MR Islam ◽

J Podder

Keyword(s):

Thin Films ◽

Activation Energy ◽

Band Gap ◽

Spray Pyrolysis ◽

Cadmium Oxide ◽

Optical Absorption Coefficient ◽

Spray Pyrolysis Method ◽

Pyrolysis Method ◽

Sem Micrograph ◽

Cdo Thin Films

Cadmium oxide (CdO) thin films have been deposited by a locally developed spray pyrolysis method onto glass substrate at 473K. The optical and electrical properties of the as-deposited and annealed films are studied in details. The surface morphology of the samples was studied by scanning electron microscopy (SEM). The SEM micrograph of as-deposited film shows uniform deposition over the substrate well. The optical absorption coefficient (Î±) of the CdO films was determined from transmittance spectra in the range of wavelength 450 - 650nm. For different thicknesses (130nm ~ 380nm) of as-deposited films, the direct band gap is found in the range of 2.40 ~2.51 eV and indirect band gap in the range of 1.97 ~ 2.20 eV. Resistivity (Ï) of CdO thin film was measured in the temperature range of 303 to 553K. The resistivity of the films of different thickness initially increases with increase in temperature and reaches a maximum at 430K and then decreases with further increase of temperature. The resistivity of the film exhibits metallic behaviour up to 430 K and above that the film behaves like a semiconductor. Activation energy (ÎE) in the semiconductor region is found in the range from 0.049 to 0.075 eV for films of thickness ranging from 160 - 285 nm. Keywords: Spray pyrolysis, CdO, Resistivity, Optical band gap, Activation energy doi: 10.3329/jbas.v32i1.2447 Journal of Bangladesh Academy of Sciences, Vol. 32, No. 1, 97-105, 2008

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Physico-Chemical Properties of CuO Thin Films Deposited by Spray Pyrolysis

Materials Science Forum ◽

10.4028/www.scientific.net/msf.895.33 ◽

2017 ◽

Vol 895 ◽

pp. 33-36 ◽

Cited By ~ 1

Author(s):

Bouzid Boudjema ◽

Radouane Daira ◽

Abdenour Kabir ◽

Rafika Djebien

Keyword(s):

Thin Films ◽

Grain Size ◽

Electrical Resistivity ◽

Band Gap ◽

Spray Pyrolysis ◽

Copper Chloride ◽

Band Gap Energy ◽

Spray Pyrolysis Method ◽

Gap Energy ◽

Uv Visible

Our work consists to the deposition of copper oxide (CuO) thin films onto glass substrates by the spray pyrolysis method. The precursor solution was copper chloride of 0.1 M and the deposition rate was 5 ml/h. The time of spray varied between 5 and 20 min and the substrate temperature was kept at 350°C. The structural, optical and electrical properties of CuO films were investigated, as a function of the spray time, by X-ray diffraction (XRD), Raman scattering, UV-visible spectroscopy in addition to the measurements of the thickness and the electrical resistivity. The obtained results indicated that our films were polycrystalline with a preferential orientation along the (111) planes. The peaks intensity as well as the grain size increased as a function of the spray time indicating the improvement of the films crystalline structure. The Raman spectroscopy confirmed the formation of the CuO phase. The UV-visible transmission varied between 36% and 53% and the band gap energy decreased from 2 to 1.72 eV as a function of the spray time. The electrical resistivity of the films decreased from 514 to 72 kΩcm and correlated with the decrease of the band gap energy and the increase of the grain size.

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Impact of Thickness on the Optical Properties of Selenium Thin Films

Ingenieria y Universidad ◽

10.11144/javeriana.iued25.itop ◽

2021 ◽

Vol 25 ◽

Author(s):

Shiva Udachan ◽

Narasimha Ayachit ◽

Lingappa Udachan ◽

Raghunanda Halembre

Keyword(s):

Thin Films ◽

Optical Properties ◽

Film Thickness ◽

Band Gap ◽

Optical Density ◽

Energy Gap ◽

Band Gap Energy ◽

Primary Objective ◽

Gap Energy ◽

The Impact

Objectives: The primary objective of this investigation is to make a systematic study on the impact of thickness on optical properties, such as energy gap, absorption coefficient, optical density etc., for selenium thin films. Understanding of the band gap energy and its influence on film thickness is of utmost importance in acquiring the intended electrical characterization of semiconducting films. Materials and methods: Ultra-purity selenium (99.99 %) was deposited on glass substrates. During deposition, the glass substrate with its holder were rotated with constant speed to have a smooth coating. Results and discussions: The XRD findings indicate that selenium is amorphous in nature. The optical band gap energy is found to be decreasing form (2.3 to 2eV) with the rise of film thickness in interval (200 to 1000 nm). The band gap energy obeys inverse square law with respect to thickness. Conclusion: We have properly grown thin films of Se below the De Broglie wavelength limit by thermal evaporation in vacuum. The optical density varies directly with film thickness. The absorption coefficients were in the interval (0.5 to 4) × 107m-1. The AFM results confirmed that the Se nano-size increases with the increase in thickness. Both the grain boundaries and sub-grain regions are clearly visible in the SEM micrographs

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Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v7i3.1581 ◽

2015 ◽

Vol 7 (3) ◽

pp. 1923-1930

Author(s):

Austine Amukayia Mulama ◽

Julius Mwakondo Mwabora ◽

Andrew Odhiambo Oduor ◽

Cosmas Mulwa Muiva ◽

Boniface Muthoka ◽

...

Keyword(s):

Thin Films ◽

Band Gap ◽

Optical Band Gap ◽

Thermal Evaporation ◽

Optical Transition ◽

Bulk Material ◽

Band Gap Energy ◽

Optical Absorbance ◽

Gap Energy ◽

Constituent Elements

Â Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 â‰¤ x â‰¤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the systemâ€™s network.

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Precise Determination of the Direct–Indirect Band Gap Energy Crossover Composition in AlxGa1-xAs

Applied Physics Express ◽

10.7567/apex.6.071201 ◽

2013 ◽

Vol 6 (7) ◽

pp. 071201 ◽

Cited By ~ 6

Author(s):

Daniel A. Beaton ◽

Kirstin Alberi ◽

Brian Fluegel ◽

Angelo Mascarenhas ◽

John L. Reno

Keyword(s):

Band Gap ◽

Band Gap Energy ◽

Precise Determination ◽

Gap Energy ◽

Indirect Band Gap

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Fabrication and Photoelectrochemical Characterization of Fe, Co, Ni and Cu-Doped TiO2 Thin Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.764.266 ◽

2013 ◽

Vol 764 ◽

pp. 266-283 ◽

Cited By ~ 8

Author(s):

Ibram Ganesh ◽

Rekha Dom ◽

P.H. Borse ◽

Ibram Annapoorna ◽

G. Padmanabham ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Metal Ions ◽

Band Gap ◽

Metal Ion ◽

Band Gap Energy ◽

Chemical Compositions ◽

Gap Energy ◽

Glass Substrates ◽

Photoelectrochemical Characterization

Different amounts of Fe, Co, Ni and Cu-doped TiO2 thin films were prepared on fluorine doped tin oxide (FTO) coated soda-lime glass substrates by following a conventional sol-gel dip-coating technique followed by heat treatment at 550 and 600°C for 30 min. These thin films were characterized for photo-current, chronoamperometry and band-gap energy values. The chemical compositions of metals-doped TiO2 thin films on FTO glass substrates were confirmed by XPS spectroscopic study. The metal-ions doped TiO2 thin films had a thickness of <200 nm="" optical="" transparency="" of="">80%, band-gap energy of >3.6 eV, and a direct band-to-band energy transition. The photoelectrochemical (PEC) studies revealed that all the metal-ions doped TiO2 thin films exhibit n-type semi-conducting behavior with a quite stable chronoamperometry and photo-currents that increase with the increase of applied voltage but decrease with the dopant metal-ion concentration in the thin film. Furthermore, these thin films exhibited flat-band potentials amenable to water oxidation reaction in a PEC cell. The 0.5 wt.% Cu-doped TiO2 thin film electrode exhibited an highest incident photon-to-current conversion efficiency (IPCE) of about 21%.

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Effect of thickness on the optical properties of Gaas thin films

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v37i1.15684 ◽

2013 ◽

Vol 37 (1) ◽

pp. 83-91 ◽

Cited By ~ 13

Author(s):

Chitra Das ◽

Jahanara Begum ◽

Tahmina Begum ◽

Shamima Choudhury

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Refractive Index ◽

Band Gap ◽

Optical Band Gap ◽

Visible Region ◽

Solar Spectrum ◽

Band Gap Energy ◽

Optical Parameters ◽

Gap Energy

Effect of thickness on the optical and electrical properties of gallium arsenide (GaAs) thin films were studied. The films of different thicknesses were prepared by vacuum evaporation method (~10-4 Pa) on glass substrates at a substrate temperature of 323 K. The film thickness was measured in situ by a frequency shift of quartz crystal. The thicknesses were 250, 300 and 500 nm. Absorption spectrum of this thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2500 nm. The values of some important optical parameters of the studied films (absorption coefficient, optical band gap energy and refractive index; extinction co-efficient and real and imaginary parts of dielectric constant) were determined using these spectra. Transmittance peak was observed in the visible region of the solar spectrum. Here transmittance showed better result when thicknesses were being increased. The optical band gap energy was decreased by the increase of thickness. The refractive index increased by increasing thickness while extinction co-efficient and real and imaginary part of dielectric constant decreased. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15684 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 83-91, 2013

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