High temperature-mediated rocksalt to wurtzite phase transformation in cadmium oxide nanosheets and its theoretical evidence

Nanoscale ◽  
2019 ◽  
Vol 11 (31) ◽  
pp. 14802-14819 ◽  
Author(s):  
Arkaprava Das ◽  
C. P. Saini ◽  
Deobrat Singh ◽  
R. Ahuja ◽  
Anumeet Kaur ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
High Temperature ◽  
Cadmium Oxide ◽  
Wurtzite Phase ◽  
Theoretical Evidence ◽  
Cdo Thin Films ◽  
Hexagonal Wurtzite Phase

A cubic rocksalt to hexagonal wurtzite phase transformation is reported with the formation of nanosheets in CdO thin films annealed at 900 °C.

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

1970 ◽  
Vol 32 (1) ◽  
pp. 97-105 ◽  
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 (α) 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 (ρ) 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 (ΔE) 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

Enhancing resistive-type hydrogen gas sensing properties of cadmium oxide thin films by copper doping

2018 ◽  
Vol 42 (2) ◽  
pp. 1457-1466 ◽  
Author(s):  
K. Sankarasubramanian ◽  
P. Soundarrajan ◽  
T. Logu ◽  
K. Sethuraman ◽  
K. Ramamurthi
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Spray Pyrolysis Technique ◽  
Cadmium Oxide ◽  
Hydrogen Gas ◽  
Chemical Spray Pyrolysis ◽  
Glass Substrates ◽  
Gas Sensing Properties ◽  
Amorphous Glass ◽  
Cdo Thin Films

The pure and Cu-doped CdO thin films with various doping concentrations (0.5 to 2 wt%) were deposited on amorphous glass substrates by a chemical spray pyrolysis technique for hydrogen gas sensor application.

scholarly journals The Effect of Doping Thiourea In CdO Thin Films For Electronic Applications

2021 ◽  
Author(s):  
Murat Soylu
Keyword(s):  
Thin Films ◽  
Structural Parameters ◽  
Cadmium Oxide ◽  
Soda Lime ◽  
Optical Transmittance ◽  
Xrd Analysis ◽  
Soda Lime Glass ◽  
Coating Method ◽  
Cdo Thin Films ◽  
P Type

Abstract Cadmium oxide (CdO) and Thiourea (Th) doped CdO thin films were deposited on soda lime glass (SLG) and crystalline p-type Si (100) substrates for various Th doping concentrations (0.3, 0.5, 0.7 at.%) using spin coating method. Some structural parameters such as the crystallite size, lattice constant, dislocation density (δ) and strain in the films were obtained from XRD analysis in which the polycrystalline structure with cubic nature and (111) prefential orientation was confirmed. CdO thin film has not shown any change in crystal phase after Th doping. The optical study emerged that the Th doping caused important changes in the transmittance, absorbance and reflectance spectra. A maximum optical transmittance (above 80%) have been obtained for 0.3% Th doped CdO thin films. Th doped CdO/p-Si heterojunctions exhibited low rectifying character and were not found to be the light sensitive.

scholarly journals Influence of bath temperature on microstructure and NH3 sensing properties of chemically synthesized CdO thin films

2019 ◽  
Vol 37 (1) ◽  
pp. 25-32
Author(s):  
A.K. Sharma ◽  
S.S. Potdar ◽  
M.A. Yewale ◽  
Deepak B. Shirgaonkar ◽  
K.S. Pakhare ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
High Temperature ◽  
Band Gap ◽  
Room Temperature ◽  
Nitrate Solution ◽  
Cadmium Nitrate ◽  
Monoclinic Crystal ◽  
Cdo Thin Films ◽  
Deposited Films

AbstractCadmium oxide (CdO) thin films were synthesized using chemical bath deposition (CBD) method from aqueous cadmium nitrate solution. The bath temperatures were maintained at room temperature (25 °C) and at higher temperature (80 °C). The structural studies revealed that the films showed mixed phases of CdO and Cd(OH)2 with hexagonal/monoclinic crystal structure. Annealing treatment removed the hydroxide phase and the films converted into pure CdO with cubic, face centered crystal structure. SEM micrographs of as-deposited films revealed nanowire-like morphology for room temperature deposited films while nanorod-like morphology for high temperature deposited films. However, cube-like morphology was observed after air annealing. Elemental composition was confirmed by EDAX analysis. Band gap energies of the as-deposited films varied over the range of 3 eV to 3.5 eV, whereas the annealed films showed band gap energy variation in the range of 2.2 eV to 2.4 eV. The annealed films were successfully investigated for NH3 sensing at different operating temperatures and at different gas concentrations. The room temperature synthesized film showed a response of 17.3 %, whereas high temperature synthesized film showed a response of 13.5 % at 623 K upon exposure to 24 ppm of NH3.

scholarly journals Annealing Effects on the Interband Transition and Optical Constants of Cobalt Doped Cadmium Oxide Thin Films

2015 ◽  
Vol 43 ◽  
pp. 81-90 ◽  
Author(s):  
Nadir F. Habubi
Keyword(s):  
Thin Films ◽  
Optical Constants ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Interband Transition ◽  
Cadmium Oxide ◽  
Spray Pyrolysis Method ◽  
Optical Parameters ◽  
Annealing Effects ◽  
Cdo Thin Films

The CdO: Co films have been deposited on substrate temperature at 400 °C by spray pyrolysis method using cadmium chloride and cobalt chloride as a precursors for Cd and Co ions, respectively. The effect of annealing temperature on optical constants of Co: CdO thin films are investigated using UV-Visible spectrophotometer in the range of (300-900) nm at room temperature. The absorbance and optical parameters such as α, n, ε1, ε2, and χ are increased when the annealing temperature increases, while the energy gap decreased from 2.5 eV before annealing to 2.48 eV after 500 °C annealing temperature. Urbach energy is increased with the increasing of annealing temperature from 353 meV for sample before annealing to 715 meV for the same samples annealed at 500 °C.

scholarly journals EFFECT OF THICKNESS ON THE STRUCTURE AND OPTICAL PROPERTIES OF LASER-INDUCED PLASMA CDO THIN FILMS

2021 ◽  
Vol 03 (03) ◽  
pp. 41-50
Author(s):  
Hiyam Ch. MAJED
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Energy Gap ◽  
Plasma Deposition ◽  
Cadmium Oxide ◽  
Laser Wavelength ◽  
Dielectric Constants ◽  
Laser Induced Plasma ◽  
Glass Substrates ◽  
Cdo Thin Films

Thin films of cadmium oxide (CdO) deposited on glass substrates using Nd-YAG laser wavelength (alpha= 532 nm) and period time (10ns) via laser-induced plasma deposition technique (PLD). The structural properties of these films have been described as a change in thickness (200 , 400 ,and 1000) nm) at substrate temperature of (400 ° C) and energy flounce of (0.4 J / cm2). The X-ray diffraction results show that he mean size of crystallite measured using Scherer formula to adjust the thickness of 200 nm, 400 nm and 1000 nm of CdO thin films is 47 nm, 64 nm and 78 nm respectively .Also the optical properties which included transmittance, absorbance , energy gap and optical constant such as the Refractive index, extinction coefficient real and imaginary parts of dielectric constants were determined .

Theoretical analysis on the sensitivity to partial pressure of oxygen of the band gap shift in CdO thin films

2016 ◽  
Vol 30 (31) ◽  
pp. 1650371 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Thin Films ◽  
Partial Pressure ◽  
Band Gap ◽  
Cadmium Oxide ◽  
Visible Region ◽  
Visible Range ◽  
Partial Pressure Of Oxygen ◽  
Sensitivity Functions ◽  
Suitable Parameter ◽  
Cdo Thin Films

With the aim of providing an analytical approach (not accurate numerical results), for the first time, the sensitivity to the partial pressure of oxygen of the shift in the energy band gap experienced by cadmium-oxide thin films is evaluated for the visible region by introducing a suitable parameter. The sensitivity to the above pressure of the spatial carrier density is determined and compared with the sensitivity relative to the band gap shift. The gradient of the CdO carrier concentration as a function of the partial pressure of oxygen appears in the expressions for the two above sensitivity functions but the goal of this paper is not computing numerically this gradient so only qualitative estimations are done. In relation to the above results, the kinetics relative to the formation of CdO thin films are investigated. In addition, the sensitivity to the pressure in question of the corresponding optical-absorption shift in the visible range is calculated.

scholarly journals The Influence of Temperature on the Formation of Cubic Structured CdO Nanoparticles and Their Thin Films from Bis(2-hydroxy-1-naphthaldehydato)cadmium(II) Complex via Thermal Decomposition Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Thokozani Xaba ◽  
Makwena J. Moloto ◽  
Mohammad A. Malik ◽  
Nosipho Moloto
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Thermal Decomposition ◽  
Metal Oxide Nanoparticles ◽  
Cadmium Oxide ◽  
Oxide Nanoparticles ◽  
Glass Substrates ◽  
Vis Spectroscopy ◽  
Cdo Nanoparticles ◽  
Cdo Thin Films

Recently, researchers have developed a great interest in the synthesis of metal oxide nanoparticles due to their potential applications in various fields of science and industry, especially in catalysis, due to their high activity. Bis(2-hydroxy-1-naphthaldehydato)cadmium(II) complexes were prepared and used as precursors for the synthesis of cadmium oxide nanoparticles via thermal decomposition method using HDA as a stabilizing agent. The prepared complexes were also used as single source precursors to prepare CdO thin films onto the glass substrates by spin coating and were annealed at 250, 300, and 350°C, respectively. The precursors were characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis, nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The synthesized CdO nanoparticles and CdO thin films were characterized by ultraviolet-visible (UV-vis) spectroscopy, photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM).

scholarly journals Effect of Annealing Temperature on Physical Properties of Indium Doped Cadmium Oxide Thin Films

2015 ◽  
Vol 11 (4) ◽  
pp. 3475-3481 ◽  
Author(s):  
Jinan A. Abd ◽  
Enas M. Al-Robayi ◽  
Zainab J. Shanan ◽  
Nadir F. Habubi
Keyword(s):  
Thin Films ◽  
Optical Transmission ◽  
Annealing Temperature ◽  
Cadmium Oxide ◽  
Optical And Electrical Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cdo Thin Films ◽  
Cdo Films

     Nanostructured indium doped CdO thin films were prepared by spray pyrolysis on glass substrate and annealed at 200-400 ᵒC for 1 hour. The structural, optical, and electrical properties of prepared films were studied using different techniques such as optical transmission, photoluminescence, X-ray diffraction, and Hall measurement. X-ray analysis shows that the In doped CdO films are preferentially orientated along (111) crystallographic directions. Increasing of annealing temperature increases the films packing density and reorient the crystallites along (1 1 1) plane.  The optical transmissions of all annealed films decreased with increasing annealing temperature. An increasing in the absorbance and photoluminescence spectra with increasing annealing temperature was denoted in all films. The band gap value of CdO:4%In equals to 2.5 eV and it decreases with annealing temperature and reaches of 2.45 eV for 400°C. The resistivity of annealed films decreased as annealing temperature increased. While high conductivity achieved in the present study is found to be 11.37 ×102 (Ω.cm)-1 for annealing at 400°C. 

Highly transparent conducting cerium incorporated CdO thin films deposited by a spray pyrolytic technique

RSC Advances ◽  
2015 ◽  
Vol 5 (124) ◽  
pp. 102741-102749 ◽  
Author(s):  
P. Velusamy ◽  
R. Ramesh Babu ◽  
K. Ramamurthi ◽  
M. S. Dahlem ◽  
E. Elangovan
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Spray Pyrolysis Technique ◽  
Cadmium Oxide ◽  
Low Level ◽  
Transparent Conducting ◽  
Cdo Thin Films

In the present work, a spray pyrolysis technique was employed to deposit cerium (Ce) doped cadmium oxide (CdO) thin films with low level doping concentrations (0.25, 0.50, 0.75 and 1.0 wt%).

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