scholarly journals Chromium-Induced Nanocrystallization of a-Si Thin Films into the Wurtzite Structure

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
K. Uma Mahendra Kumar ◽  
M. Ghanashyam Krishna
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Nanocrystalline Silicon ◽  
Spectral Transmittance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Silicides ◽  
Crystallite Sizes ◽  
Cr Addition

Chromium metal-induced nanocrystallization of amorphous silicon (a-Si) thin films is reported. The nanocrystalline nature of these films is confirmed from X-ray diffraction and Raman spectroscopy. Significantly, the deconvolution of Raman spectra reveals that the thin films were crystallized in a mixed phase of cubic diamond and wurzite structure as evidenced by the lines at 512 and 496 cm−1, respectively. The crystallite sizes were between 4 to 8 nm. Optical properties of the crystallized silicon, derived from spectral transmittance curves, revealed high transmission in the region above the band gap. Optical band gap varied between 1.3 to 2.0 eV depending on the nature of crystallinity of these films and remained unaltered with increase in Cr addition from 5 to 30%. This signifies that the electronic structure of the nanocrystalline Silicon films is not affected considerably inspite of the presence of metal silicides and the process of crystallization.

Effect of Tin Composition on Cu2ZnSnS4 Photovoltaic Absorbers

2012 ◽  
Vol 534 ◽  
pp. 156-159 ◽  
Author(s):  
Dong Hua Fan ◽  
Rong Zhang ◽  
Hui Ren Peng
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Band Gap ◽  
Crystallite Size ◽  
Optical Band Gap ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Poor Condition ◽  
Czts Thin Films

Cu2ZnSnS4 (CZTS) thin films are prepared by sulfurizing the precursors deposited by vacuum evaporation methods. The samples sulfurized at 500°C for 3h shows the strong (112) diffraction peak at 28.45˚, suggesting the successful synthesis of CZTS thin films. The X-ray diffraction shows that CZTS thin film prepared in Sn-poor condition have the best crystallinity. The Sn-dependent crystallite size was calculated to be 19.53-21.03 nm. In addition, we found that the optical band gap with various Sn contents can be modulated at 1.48-1.85 eV

Mechanism of Blue Shift of Optical Band Gap in Aluminum-Doped ZnO Thin Films with Blend Bond

2011 ◽  
Vol 685 ◽  
pp. 98-104
Author(s):  
Ling Shen ◽  
Cheng Shen ◽  
Jie Yang ◽  
Fei Xu ◽  
Zhong Quan Ma
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Optical Band Gap ◽  
Quartz Substrate ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Nano Crystalline

In this paper, aluminum–doped nano-crystalline zinc oxide (ZnO:Al or AZO) thin films were deposited on fused quartz substrate by pulsed laser ablation at various temperatures. The physical phase and surface morphology were characterized by using X-ray diffraction (XRD) and atomic force microscope (AFM), respectively. The variation of the optical band gap (Egopt) of the films with the temperature was measured through transmittance in UV-VIS wavelength. The results showed that there was a blue shift of Egoptfrom 3.44 eV to 3.62 eV as the growing temperature decreased from 500°C to 200°C. The value of Egoptimmediately recurred from 3.30 to 3.35 eV after a thermal annealing of the samples at 700 °C, inclining to a normal value of bulk zinc oxide. The analyses of XRD and AFM testified that the presence of amorphous phase in the AZO films was the main reason for the blue shift of the optical band gap Egopt.

Transparent Conductive Cu-In-O Thin Films Deposited by Reactive DC Magnetron Sputtering with Different Targets

2011 ◽  
Vol 239-242 ◽  
pp. 2752-2755
Author(s):  
Fan Ye ◽  
Xing Min Cai ◽  
Fu Ping Dai ◽  
Dong Ping Zhang ◽  
Ping Fan ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Optical Band Gap ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
Equal Distance ◽  
Transmittance Curve

Transparent conductive Cu-In-O thin films were deposited by reactive DC magnetron sputtering. Two types of targets were used. The first was In target covered with a fan-shaped Cu plate of the same radius and the second was Cu target on which six In grains of 1.5mm was placed with equal distance between each other. The samples were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/VIS spectrophotometer, four-probe measurement etc. SEM shows that the surfaces of all the samples are very smooth. EDX shows that the samples contain Cu, In as well as O, and different targets result in different atomic ratios of Cu to In. A diffraction peak related to rhombohedra-centered In2O3(012) is observed in the XRD spectra of all the samples. For both the two targets, the transmittance decreases with the increase of O2flow rates. The direct optical band gap of all the samples is also estimated according to the transmittance curve. For both the two targets, different O2flow rates result in different sheet resistances and conductivities. The target of Cu on In shows more controllability in the composition and properties of Cu-In-O films.

scholarly journals Flexible ZnO photoelectrode for photo electrochemical energy conversion

2021 ◽  
Author(s):  
T. Shiyani ◽  
Indrani Banerjee ◽  
Santosh K. Mahapatra ◽  
Asim K Ray
Keyword(s):  
Band Gap ◽  
Diffraction Pattern ◽  
Absorption Spectra ◽  
Optical Band Gap ◽  
Solar Fuels ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Pet Substrate

Abstract Photoelectrochemical properties have been investigated for flexible ZnO/ITO/PET photoelectrodes. ZnO was spin coated on ITO/PET substrate with thickness of about 310 nm. The high crystalline structure of ZnO was studied using x-ray diffraction pattern. A value of 3.4 eV has been estimated for optical band gap from its absorption spectra. The flexible ZnO photoelectrode was demonstrated to generate photoelectrochemical current. Values of 1.022 and 0.714 were found to be for photo switching and photoresponsivity, respectively. ZnO/ITO/PET can be used as a substrate for making flexible hybrid PEC devices to generate solar power and solar fuels.

Effect of Flexible Substrates on the Structural and Optical Properties of ZnO Films Deposited by Sputtering Method

2015 ◽  
Vol 1107 ◽  
pp. 678-683 ◽  
Author(s):  
Lam Mui Li ◽  
Azmizam Manie Mani ◽  
Saafie Salleh ◽  
Afishah Alias
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Low Cost ◽  
Argon Plasma ◽  
Optical Transmittance ◽  
Zno Thin Films ◽  
Plastic Substrate ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray

Zinc Oxide (ZnO) has attracted much attention because of its high optical transmittance approximately ~80 % with a wide band gap of (3.3 eV at 300 K) and a relatively low cost material. ZnO thin films were deposited on plastic substrate using RF powered magnetron sputtering method. The target used is ZnO disk with 99.99 % purity. The sputtering processes are carried out with argon gas that flow from 10-15 sccm. Argon is used to sputter the ZnO target because the ability of argon that can remove ZnO layer effectively by sputtering with argon plasma bombardment. The deposited ZnO thin films are characterized using X-Ray Diffraction (XRD) and UV-Vis Spectrometer. The analysis of X-ray diffraction show that good crystalline quality occurs at nominal thickness of 400 nm. The optical studies showed that all the thin films have high average transmittance of approximately 80 % and the estimated value of optical band gap is within 3.1 eV-3.3 eV range.

Deposition of Nano Fiber ZnO and Zn1-xCdxO Thin Films by a Simple Spray Pyrolysis and Characterizations for Optoelectronic Applications

2012 ◽  
Vol 545 ◽  
pp. 100-104 ◽  
Author(s):  
J. Podder ◽  
M.R Islam
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Optical Band Gap ◽  
Zinc Alloy ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Nano Fiber ◽  
Cadmium Zinc

ZnO and Zn1-xCdxO thin films have been deposited onto glass substrate using spray pyrolysis at 200°C. Cadmium-zinc alloy thin films have been prepared by taking different concentrations of cadmium (Cd). The elemental analysis and the surface morphology of the films were carried by the energy dispersive X-ray (EDX) and scanning electron microscopy (SEM). The EDX data show that the films are highly stoichiometric. The SEM images show that the film changes from nano fiber to grain with the increase of Cd concentrations. The X-ray diffraction pattern shows that the films are polycrystalline in nature. The crystal structure of the films changes from hexagonal-ZnO to cubic-CdO depending on the concentration of Zn and Cd in the Zn1-xCdxO films. The optical properties of these films were studied by UV-VIS spectroscopy. The optical band gap of the films was changed from 3.2 to 2.4 with the variation of cadmium.

Preparation of CuIn(SxSe1–x)2 thin films with tunable band gap by controlling sulfurization temperature of CuInSe2

2010 ◽  
Vol 25 (12) ◽  
pp. 2426-2429 ◽  
Author(s):  
Guangjun Wang ◽  
Gang Cheng ◽  
Binbin Hu ◽  
Xiaoli Wang ◽  
Shaoming Wan ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Band Gap ◽  
Low Cost ◽  
Chalcopyrite Structure ◽  
X Ray Diffraction ◽  
Large Area ◽  
X Ray ◽  
Sulfurization Temperature ◽  
Tunable Band Gap

In this paper, polycrystalline CuIn(SxSe1–x)2 thin films with tunable x and Eg (band gap) values were prepared by controlling the sulfurization temperature (T) of CuInSe2 thin films. X-ray diffraction indicated the CuIn(SxSe1–x)2 films exhibited a homogeneous chalcopyrite structure. When T increases from 150 to 500 °C, x increases from 0 to 1, and Eg increases from 0.96 to 1.43 eV. The relations between x and Eg and the sulfurization process of CuIn(SxSe1–x)2 thin films have been discussed. This work provides an easy and low-cost technique for preparing large area absorber layers of solar cell with tunable Eg.

Growth, Optical Adsorption and Resistivity of (Ga0.6In0.4)2Se3 and (Ga0.594In0.396Er0.01)2Se3 Single Crystals

2013 ◽  
Vol 200 ◽  
pp. 50-53
Author(s):  
Inna A. Ivashchenko ◽  
Volodumur V. Halyan ◽  
Irina V. Danylyuk ◽  
Volodumur Z. Pankevuch ◽  
Georgij Y. Davydyuk ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
Band Gap ◽  
Single Crystals ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Xrd Method

The phase diagram of the Ga2Se3–In2Se3 system was investigated by differential-thermal analysis (DTA) and X-ray diffraction (XRD) method. The single crystals from the area of existence of the γ2 phase with the compositions (Ga0.6In0.4)2Se3 and (Ga0.594In0.396Er0.01)2Se3 were grown by a vertical Bridgman method. Absorption spectra of the grown crystals were studied. The estimated optical band gap is 1.95±0. 01 eV. The resistance of the single crystals of (Ga0.6In0.4)2Se3 (R=500 MΩ) and (Ga0.594In0.396Er0.01)2Se3 (R=210 MΩ) was measured.

Effect of bath temperature on the chemical bath deposition of PbSe thin films

1970 ◽  
Vol 6 (2) ◽  
pp. 126-132 ◽  
Author(s):  
Anuar Kassim ◽  
Tan Wee Tee ◽  
Ho Soon Min ◽  
Shanthi Monohorn ◽  
Saravanan Nagalingam
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Chemical Bath Deposition ◽  
Lead Nitrate ◽  
Bath Temperature ◽  
Band Gap Energy ◽  
Sodium Selenate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gap Energy

PbSe thin films are prepared by chemical bath deposition technique over microscope glass substrates from an aqueous acidic bath containing lead nitrate and sodium selenate. The influence of bath temperature on the properties of PbSe film is investigated. The X-ray diffraction analysis showed the deposited films were polycrystalline and having the (111) orientation. The surface morphology study revealed that the grains have cubic shape crystal. The band gap energy was decreased from 2.0 to 1.3 eV as the bath temperature was increased from 40 to 80°C. The films deposited at 80°C showed good crystallinity and uniformly distributed over the surface of substrate with larger grain sizes. Therefore, the optimum bath temperature is 80°C. Keywords: Lead selenide; X-ray diffraction; Band gap energy; Chemical bath deposition; Thin films DOI: 10.3126/kuset.v6i2.4021Kathmandu University Journal of Science, Engineering and Technology Vol.6. No II, November, 2010, pp.126-132

Electrosynthesis and Studies on CdZnSe Thin Films

2011 ◽  
Vol 15 (1) ◽  
pp. 37-42
Author(s):  
T. Mahalingam ◽  
V. Dhanasekaran ◽  
S. Rajendran ◽  
R. Chandramohan ◽  
Luis Ixtlilco ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Band Gap ◽  
Ph Value ◽  
Bath Temperature ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
Sem Images ◽  
X Ray ◽  
Predominant Orientation ◽  
Diffraction Patterns

Electrodeposited CdZnSe thin films have been prepared at various bath temperatures. The thickness of the films was estimated between 850 nm and 1500 nm by stylus method. The X-ray diffraction patterns revealed that the polycrystalline nature with cubic structure of CdZnSe alloy thin films. Microstructural properties such as, crystallite size, dislocation density, microstrain and number of crystallites per unit area were calculated using predominant orientation of the films. SEM images revealed that the surface morphology could be tailored suitably by adjusting the pH value during deposition. The surface roughness of the film was estimated using topographical studies. Optical properties of the film were analyzed from absorption and transmittance studies. Optical band gap of the films increased from 1.67 to 1.72 eV with the increase of bath temperature from 30 to 90℃. The optical constants (refractive index (n) and extinction coefficient (k)) of CdZnSe thin films were evaluated using optical studies.

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