Preparation of crystalline CdSe particles by chemical bath deposition

1998 ◽  
Vol 13 (12) ◽  
pp. 3394-3398 ◽  
Author(s):  
Osamu Yamamoto ◽  
Tadashi Sasamoto ◽  
Michio Inagaki
Keyword(s):  
Band Gap ◽  
Crystalline Phase ◽  
Sodium Sulfite ◽  
Precursor Solution ◽  
Atomic Ratio ◽  
Band Gap Energy ◽  
Complexing Agent ◽  
Gap Energy ◽  
A Value ◽  
Type Phase

Crystalline CdSe particles were prepared by keeping the precursor solutions at temperatures above 60 °C. It was essential to use sodium sulfite as a stabilizing agent for selenium ions and sodium dicarboxylate as a complexing agent for cadmium in the precursor solution. The principal crystalline phase of the samples obtained at 60 °C was a cubic zincblende-type phase, but those prepared at 80 °C coexisted with a hexagonal wurtzite-type phase. The ratio of cadmium to selenium in the samples decreased with an increase of the concentration of selenourea in the precursor solutions, irrespective of the kind of complex agents and the keeping time of the precursor solutions. The band-gap energy of CdSe with an atomic ratio (Cd/Se) of 1 showed a value of 1.74 eV, but that with the ratio of 2.3 gave a slightly smaller value of 1.42 eV.

scholarly journals Copper Oxide Films Deposited by Microwave Assisted Alkaline Chemical Bath

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 968
Author(s):  
Reina Galeazzi Isasmendi ◽  
Isidro Juvenal Gonzalez Panzo ◽  
Crisóforo Morales-Ruiz ◽  
Román Romano Trujillo ◽  
Enrique Rosendo ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Copper Oxide ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Precursor Solution ◽  
Band Gap Energy ◽  
X Ray ◽  
Gap Energy ◽  
Glass Substrates ◽  
Microwave Assisted

Copper oxide (CuO) films were deposited onto glass substrates by the microwave assisted chemical bath deposition method, and varying the pH of the solution. The pH range was varied from 11.0 to 13.5, and the effects on the film properties were studied. An analytical study of the precursor solution was proposed to describe and understand the chemical reaction mechanisms that take place in the chemical bath at certain pH to produce the CuO film. A series of experiments were performed by varying the parameters of the analytical model from which the CuO films were obtained. The crystalline structure of the CuO films was studied using X-ray diffraction, while the surface morphology, chemical composition, and optical band-gap energy were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–Vis spectrophotometry, respectively. The CuO films obtained exhibited a monoclinic crystalline phase, nanostructured surface morphology, stoichiometric Cu/O ratio of 50/50 at%, and band-gap energy value of 1.2 eV.

Control of the Formation of Zn1-xMgxO Films by Zinc Sulfate Concentration

2013 ◽  
Vol 1494 ◽  
pp. 83-89
Author(s):  
Hiroki Ishizaki ◽  
Seishiro Ito
Keyword(s):  
Band Gap ◽  
Zinc Sulfate ◽  
Optical Band Gap ◽  
Atomic Ratio ◽  
Band Gap Energy ◽  
Magnesium Nitrate ◽  
Zno Films ◽  
Sulfate Concentration ◽  
Gap Energy ◽  
Conductive Glass

ABSTRACTMagnesium doped ZnO films were electrochemically grown on the NESA conductive glass substrate from the magnesium nitrate aqueous solution with zinc sulfate, kept at 323K and the cathodic potential of -0.9V vs. Ag/AgCl. The Mg/(Mg+Zn) atomic ratio of Zn1-xMgxO films increased with the decrease in the zinc sulfate concentration. The optical band gap energy of these Zn1-xMgxO films decreased with increasing content of zinc sulfate. Thus, the optical band gap energy and Mg/(Mg+Zn) atomic ratio of Zn1-xMgxO films would depend on the zinc sulfate concentration.

scholarly journals Effect of Annealing on Optical Properties of Zinc Oxide Thin Films Prepared by Homemade Spin Coater

2015 ◽  
Vol 15 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Deependra Das Mulmi ◽  
Agni Dhakal ◽  
Buddha Ram Shah
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Precursor Solution ◽  
Infrared Region ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Gap Energy ◽  
Glass Substrates ◽  
Near Ultraviolet

Zinc oxide (ZnO) thin films were deposited on the ordinary glass substrates by spin coating method. The precursor solution was prepared by mixing zinc acetate dehydrate in appropriate proportions with ethanol and diethanolamine (DEA). The obtained thin films were dried at 200°C for 15 minutes in hot air oven. Crystalline ZnO thin films were achieved following annealing process at temperatures 300°, 400° and 500°C for 2 hours. Thin films as- prepared were studied by X-ray diffraction and UV-visible spectroscopy. The films were transparent from near ultraviolet to infrared region. Optical band gap energy of ZnO was obtained 3.22 eV at 300°C. On annealing at 400° and 500°C, band gap energy was shifted at 3.14 eV and 3.05 eV respectively.DOI: http://dx.doi.org/njst.v15i2.12126Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 111-116

scholarly journals Influence of deposition temperature on structural, morphological, and optical properties of ZnS thin films

2018 ◽  
Vol 96 (7) ◽  
pp. 826-830
Author(s):  
Sinan Temel
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Band Gap ◽  
Deposition Temperature ◽  
Band Gap Energy ◽  
Complexing Agent ◽  
Gap Energy ◽  
Nanostructured Particles ◽  
Glass Substrates

ZnS thin films were deposited onto glass substrates by chemical bath deposition (CBD) technique at different deposition temperatures (75, 80, 85, 90 °C) with non-toxic complexing agent tri-sodium citrate. Effects of deposition temperature on structural, morphological, and optical properties of thin films were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectroscopy, respectively. The XRD results show that all produced ZnS thin films have cubic structure. The calculated grain size values are between 13 and 26 nm. It was observed that the grain size values increase and crystallization of films improve as the deposition temperature increases. The FESEM images reveal that film surfaces are formed by almost homogeneously dispersed nanostructured particles. Optical characterization results show that ZnS thin films have high transmittance of about 80% in the range of 400–800 nm with band gap energy values between 3.52 and 3.65 eV. As the deposition temperature increases, the band gap energy values increase. According to these results, it was observed that the structural, morphological, and optical properties of ZnS films vary depending on the deposition temperature.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

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

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

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 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 system’s network.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

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