scholarly journals Enhanced Photoelectrochemical Response of Zn-Dotted Hematite

2007 ◽  
Vol 2007 ◽  
pp. 1-6 ◽  
Author(s):  
Saroj Kumari ◽  
Aadesh P. Singh ◽  
Chanakya Tripathi ◽  
Diwakar Chauhan ◽  
Sahab Dass ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spray Pyrolysis ◽  
Pore Diameter ◽  
Thermal Evaporation ◽  
Photocurrent Density ◽  
Optimum Thickness ◽  
Thermal Evaporation Method ◽  
Donor Density ◽  
Photoelectrochemical Response

Photoelectrochemical response of thin films ofα-Fe2O3, Zn dopedα-Fe2O3, and Zn dots deposited on dopedα-Fe2O3prepared by spray pyrolysis has been studied. Samples of Zn dots were prepared using thermal evaporation method by evaporating Zn through a mesh having pore diameter of 0.7 mm. The presence of Zn-dotted islands on dopedα-Fe2O3surface exhibited significantly large photocurrent density as compared to other samples. An optimum thickness of Zn dots∼230 Å is found to give enhanced photoresponse. The observed results are analyzed with the help of estimated values of resistivity, band gap, flatband potential, and donor density.

scholarly journals Structure, Morphology and Opto-Electrical Properties of Nanostructured Indium Doped SnO2 Thin Films Deposited by Thermal Evaporation

2016 ◽  
Vol 12 (27) ◽  
pp. 263 ◽  
Author(s):  
Md. Mahafuzur Rahaman ◽  
Kazi Md. Amjad Hussain ◽  
Mehnaz Sharmin ◽  
Chitra Das ◽  
Shamima Choudhury
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
High Vacuum ◽  
Optical Transmittance ◽  
Visible Range ◽  
Average Crystalline Size ◽  
Thermal Evaporation Method ◽  
Double Beam

Indium doped Tin oxide (SnO2: In) thin films of various thicknesses (200-600 nm) with fixed 2% indium (In) concentration were prepared by thermal evaporation method onto glass substrates under high vacuum (10-6 Torr). As deposited films were vacuum annealed at 200o C for 60 minutes. The structure, optical, electrical and morphology properties of SnO2: In thin films were investigated as a function of film thickness. The XRD analysis revealed that films were polycrystalline in nature with a tetragonal structure having (110) plane as the preferred orientation. The average crystalline size increased from 34.8 to 51.25 nm with increase of film thicknesses. The surface morphology of the doped films was obtained by Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM). Optical transmittance was obtained from a double beam UV-Vis- NIR spectrophotometer. Maximum transmittance varied from 65-76% in the visible range of the spectrum. Optical band gap (Eg) varied between 2.89 and 3.20 eV. The resistivity of SnO2: In thin films was as high as 105 Ω-cm. Activation energy of the films were found to be 0.18 to 0.47 eV for 300-600 nm film thicknesses. Due to high optical band gap and high electrical resistivity, these nanostructured films can be used in optoelectronic devices especially as opto-insulator.

scholarly journals Inorganic and Lead-free CsBi3I10 Thin Film Solar cell Prepared by Single-source Thermal Evaporation

2021 ◽  
Author(s):  
Huabin Lan ◽  
Xingye Chen ◽  
Ping Fan ◽  
Guangxing Liang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Band Gap ◽  
Thermal Evaporation ◽  
Perovskite Solar Cells ◽  
Lead Free ◽  
Single Source ◽  
Thermal Evaporation Method ◽  
Inorganic Lead

Abstract All inorganic lead-free halide perovskites have attracted much attention due to their non-toxic and good band gap. In this paper, we first prepared all inorganic lead-free perovskite CsBi3I10 thin films by single source thermal evaporation deposition. The results show that CsBi3I10 thin films prepared by single source thermal evaporation have layered structure, high purity hexagonal phase and high crystallinity, which are consistent with the theoretical calculation results. The surface of the thin film was compact and uniform, and had high homology with the crystal structure of the evaporation source material. After annealing, the crystallinity of the film was further improved. The band gap of the CsBi3I10 thin film calculated was 1.83 eV, Perovskite solar cells based on CsBi3I10 thin films exhibit an efficiency of up to 0.84%. These results indicate that the proposed single source thermal evaporation method has the potential to prepare high efficiency inorganic lead-free perovskite 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.

X- ray diffraction and dielectric properties of PbSe thin films

2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan
Keyword(s):  
Thin Films ◽  
Thermal Activation ◽  
Thermal Evaporation ◽  
Thermal Activation Energy ◽  
Dielectric Constants ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.

Band Gap Engineering in Spray Pyrolysis Grown Nanocrystalline NiO Thin Films by Fe Doping

2019 ◽  
Vol 11 (4) ◽  
pp. 04015-1-04015-6
Author(s):  
H. S. Gavale ◽  
◽  
M. S. Wagh ◽  
S. R. Gosavi ◽  
◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spray Pyrolysis ◽  
Fe Doping ◽  
Band Gap Engineering

scholarly journals Preparation of InSe Thin Films by Thermal Evaporation Method and Their Characterization: Structural, Optical, and Thermoelectrical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Sarita Boolchandani ◽  
Subodh Srivastava ◽  
Y. K. Vijay
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Temperature Variation ◽  
Thermal Evaporation ◽  
Low Cost ◽  
High Vacuum ◽  
Power Measurement ◽  
Thermal Evaporation Method ◽  
Evaporation Method

The indium selenium (InSe) bilayer thin films of various thickness ratios, InxSe(1-x) (x = 0.25, 0.50, 0.75), were deposited on a glass substrate keeping overall the same thickness of 2500 Ǻ using thermal evaporation method under high vacuum atmosphere. Electrical, optical, and structural properties of these bilayer thin films have been compared before and after thermal annealing at different temperatures. The structural and morphological characterization was done using XRD and SEM, respectively. The optical bandgap of these thin films has been calculated by Tauc’s relation that varies within the range of 1.99 to 2.05 eV. A simple low-cost thermoelectrical power measurement setup is designed which can measure the Seebeck coefficient “S” in the vacuum with temperature variation. The setup temperature variation is up to 70°C. This setup contains a Peltier device TEC1-12715 which is kept between two copper plates that act as a reference metal. Also, in the present work, the thermoelectric power of indium selenide (InSe) and aluminum selenide (AlSe) bilayer thin films prepared and annealed in the same way is calculated. The thermoelectric power has been measured by estimating the Seebeck coefficient for InSe and AlSe bilayer thin films. It was observed that the Seebeck coefficient is negative for InSe and AlSe thin films.

scholarly journals Influence of Ag-Dopant on Structural Optical and Electrical Properties of Cu(1-x)AgxO Thin Films Prepared By Chemical Spray Pyrolysis Technique

2018 ◽  
Vol 4 (5) ◽  
pp. 542-545 ◽  
Author(s):  
R. Shabu ◽  
A. Moses Ezhil Raj
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spray Pyrolysis ◽  
Optical Band Gap ◽  
Spray Pyrolysis Technique ◽  
Precursor Solution ◽  
Oxide Semiconductor ◽  
Chemical Spray Pyrolysis ◽  
Chemical Spray Pyrolysis Technique ◽  
Chemical Spray

As major attention has been paid to transition metal oxide semiconductor suitable for solar cell, photo detector and gas sensor, present study embark on the structural, optical and electrical characterization of Ag doped CuO thin films prepared using chemical spray pyrolysis technique at the constant substrate temperature of 350 �C. For Ag doping, various concentrations of silver acetate (0.5-3.0 wt.%) was used in the sprayed precursor solution. Confirmed monoclinic lattice shows the tenorite phase formation of CuO in the pure and Ag doped films. The optical band gap of the films was in the range of 2.4 -3.4 eV. A minimum resistivity of 0.0017x103 ohmcm was achieved in the 0.5 wt.% Ag doped film, and its optical band gap was 2.74 eV.

scholarly journals Annealing Effect on the Thermoelectric Properties of Bi2Te3Thin Films Prepared by Thermal Evaporation Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jyun-Min Lin ◽  
Ying-Chung Chen ◽  
Chi-Pi Lin
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Thermal Evaporation Method ◽  
Si Substrates ◽  
Seebeck Coefficients

Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

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

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