High Quality, Low Cost Continuous Poly-GaN Film on Si and Glass Substrates Produced by Spin Coating

2004 ◽  
Vol 831 ◽  
Author(s):  
Huaqiang Wu ◽  
Athanasios Bourlinos ◽  
Emmanuel P. Giannelis ◽  
Michael G. Spencer
Keyword(s):  
Spin Coating ◽  
Low Cost ◽  
Methyl Cellulose ◽  
Colloidal Dispersions ◽  
X Ray Diffraction ◽  
High Quality ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Glass Substrates ◽  
Strong Luminescence

ABSTRACTPolycrystalline GaN layers have been produced on generic substrates via spin coating. Based on X-ray diffraction and SEM analyses, the GaN particles appear to be highly oriented on the surface. Strong luminescence from these layers has been demonstrated by cathodoluminescence. The source material was high purity, high quality GaN powder produced in our laboratory. Methyl cellulose was successfully used to disaggregate GaN particles in the dispersion. The colloidal dispersions were spun onto different substrates: Si, sapphire and glass. The dispersant was removed by annealing the sample at 500°C. The layer thickness was controlled by varying the number of spin coatings. Applications for spindeposited GaN layers include the fields of light emitting devices and random lasers.

Thermal conversion of CBD grown ZnS thin films to ZnO

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kooliyankal Naseema ◽  
Kaniyamkandy Ribin ◽  
Nidiyanga Navya ◽  
Prasoon Prasannan
Keyword(s):  
Thin Films ◽  
Low Cost ◽  
Thermal Conversion ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Glass Substrates ◽  
Anion Substitution ◽  
Nano Crystalline ◽  
Before And After ◽  
Uv Visible

AbstractNano crystalline zinc sulfide thin films were deposited onto glass substrates by chemical bath deposition method. One of the samples was annealed at 300 °C for 2 h in air using a muffle furnace. The prepared thin films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and Raman spectroscopy (FT-R) studies before and after annealing. The analysis confirmed the thermal-induced anion substitution and conversion of ZnS crystal to ZnO wurtzite crystal. XRD pattern showed that these films were phase pure and polycrystalline in nature. Optical band gap was found to be 3.86 eV for ZnS and 3.21 eV for ZnO. The films prepared by this simple, low-cost technique are suitable for photovoltaic and optoelectronic applications.

scholarly journals Characterization of Electrodeposited Cadmium Selenide Thin Films

2012 ◽  
Vol 60 (1) ◽  
pp. 137-140 ◽  
Author(s):  
RI Chowdhury ◽  
MS Islam ◽  
F Sabeth ◽  
G Mustafa ◽  
SFU Farhad ◽  
...  
Keyword(s):  
Thin Films ◽  
Cadmium Selenide ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Cdse Film ◽  
Cell Structures ◽  
Deposited Film ◽  
Deposited Films

Cadmium selenide (CdSe) thin films have been deposited on glass/conducting glass substrates using low-cost electrodeposition method. X-ray diffraction (XRD) technique has been used to identify the phases present in the deposited films and observed that the deposited films are mainly consisting of CdSe phases. The photoelectrochemical (PEC) cell measurements indicate that the CdSe films are n-type in electrical conduction, and optical absorption measurements show that the bandgap for as-deposited film is estimated to be 2.1 eV. Upon heat treatment at 723 K for 30 min in air the band gap of CdSe film is decreased to 1.8 eV. The surface morphology of the deposited films has been characterized using scanning electron microscopy (SEM) and observed that very homogeneous and uniform CdSe film is grown onto FTO/glass substrate. The aim of this work is to use n-type CdSe window materials in CdTe based solar cell structures. The results will be presented in this paper in the light of observed data.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10352  Dhaka Univ. J. Sci. 60(1): 137-140 2012 (January)

Impact of various reactant concentrations on the morphology and photoluminescence property of synthetic ZnO nanobelts

2017 ◽  
Vol 31 (35) ◽  
pp. 1750337
Author(s):  
Guoxuan Qin ◽  
Yanan Wang ◽  
Shentong Mo ◽  
Xing Fu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Photoluminescence Property ◽  
Xrd Analysis ◽  
Maximum Temperature ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
X Ray ◽  
Light Emitting Devices ◽  
Uv Emission ◽  
Zno Nanomaterials ◽  
Fluorescence Spectrometer

In this paper, ZnO nanobelts have been partially high-quality synthesized employing diverse reactant mass ratios between zinc acetate [Zn(AC)2] and polyvinyl alcohol (PVA) without any catalyst. The maximum temperature required for the whole reaction process is no more than 650[Formula: see text]C. The morphologies of ZnO nanomaterials fabricated from distinct reactant concentrations have been systematically investigated by means of field-emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) analysis identifies that ZnO nanobelts exhibit a typical wurtzite structure. Through fluorescence spectrometer, the photoluminescence (PL) spectra generated by ZnO nanomaterials corresponding to different reactant concentrations have disparate peak intensities and luminescence wavelengths. This phenomenon indicates that novel-synthesized ZnO nanomaterial shows great potential in changing the optical properties of light-emitting devices. In addition, synthetic ZnO nanobelts exhibit excellent UV emission capability.

scholarly journals Low-Cost Synthesis of Cu-Modified Immobilized Nanoporous TiO2 for Photocatalytic Degradation of 1H-Benzotriazole

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Tihana Čižmar ◽  
Ivana Panžić ◽  
Krešimir Salamon ◽  
Ivana Grčić ◽  
Lucija Radetić ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Spin Coating ◽  
Low Cost ◽  
Electrochemical Anodization ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Titanium Foils ◽  
The Given

Cu-modified immobilized nanoporous TiO2 photocatalysts, prepared by electrochemical anodization of titanium foils, were obtained via four different synthesis methods: hydrothermal synthesis, anodization with Cu source, electrodeposition, and spin-coating, using two different copper sources, Cu(NO3)2 and Cu(acac)2. The objective of this research was to investigate how copper modifications can improve the photocatalytic activity of immobilized nanoporous TiO2 under the UV/solar light irradiation. The best photocatalytic performances were obtained for Cu-modifications using spin-coating. Therefore, the effect of irradiated catalyst surface areas on the adsorption of model pollutants, methylene blue (MB) and 1H-benzotriazole (BT), was examined for samples with Cu-modification by the spin-coating technique. The mechanisms responsible for increased degradation of MB and BT at high Cu concentrations (0.25 M and 0.5 M) and decreased degradation at low Cu loadings (0.0625 M and 0.125 M) were explained. 1H-benzotriazole was used to study the photocatalytic activity of the given samples because it is highly toxic and present in most water systems. The characterization of the synthesized Cu-modified photocatalysts in terms of phase composition, crystal structure, and morphology were investigated using X-ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, and Energy Dispersive X-ray spectroscopy.

scholarly journals White LEDs: Ultra‐Efficient and High‐Quality White Light‐Emitting Devices using Fluorescent Proteins in Aqueous Medium (Adv. Mater. Technol. 6/2020)

2020 ◽  
Vol 5 (6) ◽  
pp. 2070035
Author(s):  
Sadra Sadeghi ◽  
Rustamzhon Melikov ◽  
Deniz Conkar ◽  
Elif Nur Firat‐Karalar ◽  
Sedat Nizamoglu
Keyword(s):  
Aqueous Medium ◽  
White Light ◽  
Fluorescent Proteins ◽  
High Quality ◽  
Light Emitting ◽  
White Leds ◽  
Light Emitting Devices

Heteroepitaxy of GaN on Silicon: In Situ Measurements

2005 ◽  
Vol 483-485 ◽  
pp. 1051-1056
Author(s):  
A. Krost ◽  
Armin Dadgar ◽  
F. Schulze ◽  
R. Clos ◽  
K. Haberland ◽  
...  
Keyword(s):  
Low Cost ◽  
Group Iii Nitrides ◽  
In Situ Monitoring ◽  
Attractive Alternative ◽  
Light Emitting ◽  
Group Iii ◽  
Light Emitting Devices ◽  
Thermal Expansion Coefficients ◽  
Long Time

Due to the lack of GaN wafers, so far, group-III nitrides are mostly grown on sapphire or SiC substrates. Silicon offers an attractive alternative because of its low cost, large wafer area, and physical benefits such as the possibility of chemical etching, lower hardness, good thermal conductivity, and electrical conducting or isolating for light emitting devices or transistor structures, respectively. However, for a long time, a technological breakthrough of GaN-on-silicon has been thought to be impossible because of the cracking problem originating in the huge difference of the thermal expansion coefficients between GaN and silicon which leads to tensile strain and cracking of the layers when cooling down. However, in recent years, several approaches to prevent cracking and wafer bowing have been successfully applied. Nowadays, device-relevant thicknesses of crackfree group-III-nitrides can be grown on silicon. To reach this goal the most important issues were the identification of the physical origin of strains and its engineering by means of in situ monitoring during metalorganic vapor phase epitaxy.

IMPROVED PROPERTIES OF SnO2 THIN FILMS OBTAINED VIA SPIN COATING METHOD BY VARYING THE SOLUTION CONCENTRATION

2018 ◽  
Vol 25 (04) ◽  
pp. 1850092
Author(s):  
SOUMIA BELHAMRI ◽  
NASR-EDDINE HAMDADOU
Keyword(s):  
Spin Coating ◽  
Visible Spectrum ◽  
Optical Transmittance ◽  
Solution Concentration ◽  
X Ray Diffraction ◽  
Film Properties ◽  
Average Roughness ◽  
Arithmetic Average ◽  
Glass Substrates ◽  
Coating Method

The aim of this work is to study the solution concentration effect on the SnO2 thin film properties, which were deposited on glass substrates by spin coating technique and annealed for one hour at 500[Formula: see text]C. X-ray diffraction (XRD) spectra show that the films deposited at various solution concentrations (0.5[Formula: see text]mol/L, 0.7[Formula: see text]mol/L and 1[Formula: see text]mol/L) are polycrystalline with a tetragonal rutile type. Grains have two preferred orientations along the directions (110) and (101) corresponding to 2[Formula: see text] equal to 26.74[Formula: see text] and 34.11[Formula: see text], respectively. We have also noted that the grain size changes between 109[Formula: see text]nm and 178[Formula: see text]nm. However, the film coated at 10 deposition cycles and 0.7[Formula: see text]mol/L solution concentration has a minimum arithmetic average roughness of 0.376 nm. The optical transmittance of the films in the visible spectrum was in the range of 77–84% and the optical band gap gradually decreases with the decrease of the solution concentration from 4.11[Formula: see text]eV to 3.56[Formula: see text]eV.

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