scholarly journals Optical Properties of Al- and Sb-Doped CdTe Thin Films

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
A. A. J. Al-Douri ◽  
F. Y. Al-Shakily ◽  
M. F. A. Alias ◽  
A. A. Alnajjar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Transition ◽  
Coefficient Increase ◽  
Evaporation Technique ◽  
Direct Optical Transition ◽  
Cdte Thin Films ◽  
Substrate Temperatures

Nondoped and (Al, Sb)-doped CdTe thin films with 0.5, 1.5, and 2.5  wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures () of room temperature (RT) and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n), extinction coefficient (), and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant asn, and real and imaginary parts of the dielectric coefficient increase.

scholarly journals Optical properties of CuSe thin films - band gap determination

2017 ◽  
Vol 49 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Milica Petrovic ◽  
Martina Gilic ◽  
Jovana Cirkovic ◽  
Maja Romcevic ◽  
Nebojsa Romcevic ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Nir Spectroscopy ◽  
Copper Selenide ◽  
Photoluminescence Spectra ◽  
Indirect Transition ◽  
Direct Transition ◽  
Scanning Electron

Copper selenide thin films of three different thicknesses have been prepared by vacuum evaporation method on a glass substrate at room temperature. The optical properties of the films were investigated by UV-VIS-NIR spectroscopy and photoluminescence spectroscopy. Surface morphology was investigated by field-emission scanning electron microscopy. Copper selenide exhibits both direct and indirect transitions. The band gap for direct transition is found to be ~2.7 eV and that for indirect transition it is ~1.70 eV. Photoluminescence spectra of copper selenide thin films have also been analyzed, which show emission peaks at 530, 550, and 760 nm. The latter corresponds to indirect transition in investigated material.

scholarly journals The Role of Dopant Concentration on Conductivity and Mobility of CdTe Thin Films

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Ala J. Al-Douri ◽  
F. Y. Al-Shakily ◽  
Abdalla A. Alnajjar ◽  
Maysoon F. A. Alias
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Dopant Concentration ◽  
Glass Substrates ◽  
Order Of Magnitude ◽  
Cdte Thin Films ◽  
P Type ◽  
Substrate Temperatures

Films of CdTe pure and doped with various atomic percentages of Al and Sb (0.5, 1.5 & 2.5) were prepared, and their electrical properties were investigated. The films were prepared by thermal evaporation on glass substrates at two substrate temperatures (Ts=RT& 423 K). The results showed that the conduction phenomena of all the investigated CdTe thin films on glass substrates are caused by two distinct mechanisms. Room temperature DC conductivity increases by a factor of four for undoped CdTe thin films asTsincreases and by 1-2 orders of magnitude with increasing dopant percentage of Al and Sb. In general, films doped with Sb are more efficient than Al-doped films. The activation energy (Ea2) decreases with increasingTsand dopant percentage for both Al and Sb. Undoped CdTe films deposited at RT are p-type convert to n-type with increasingTsand upon doping with Al at more than 0.5%. The carrier concentration decreases asTsincreases while it increases with increasing dopant percentage. Hall mobility decreases more than three times as Al increases whereas it increases about one order of magnitude with increasing Sb percentage in CdTe thin films deposited at 423 K and RT, respectively.

scholarly journals Influence of Air Annealing and Gamma Ray Irradiation on the Optical Properties of Cl16FePc Thin Films

2012 ◽  
Vol 9 (4) ◽  
pp. 2439-2445 ◽  
Author(s):  
Raji Koshy ◽  
C. S. Menon
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Optical Absorption ◽  
Band Gap ◽  
Gamma Ray ◽  
Optical Transition ◽  
High Electron ◽  
Glass Substrates ◽  
Optical Dielectric Constant

Metal phthalocyanines are one of the most promising candidates to be used in the fabrication of such devices. Among various phthalocyanines, Iron Hexadecachloro Phthalocyanine (Cl16FePc) has received less attention. Basic characteristics of Cl16FePc are not reported in literature. Hexadecacholoro phthalocyanines have attracted interest as possible n-type organic semiconductor with high electron mobility and good stability characteristics. In the present work we investigate the optical band gap of the Cl16FePc thin films from the optical absorption spectrum as a function of air annealing temperatures and their suitability for the fabrication of molecular electronic devices. Some optical properties of the samples were studied as a function of γ-radiation doses also. Optical transition is found to be of direct type and optical band gaps are determined by analyzing the absorption spectrum. Vacuum sublimed thin films of Iron hexadecachloro phthalocyanine were prepared at room temperature onto glass substrates at a base pressure of 10-5Torr on precleaned glass substrates using Hind Hivac 12A4 coating plant. The optical energy band gap Eg were calculated. The mechanism of optical absorption follow the rule of direct transition. In the present paper we also report refractive index, real and imaginary parts of optical dielectric constant etc. from the reflectance measurements.

scholarly journals Investigation the effect of annealing temperature on the optical properties of CdSe thin films

2018 ◽  
Vol 6 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Sabah M. Ahmed ◽  
Raghad Y. Mohammed ◽  
Sedki O. Yousif
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Transmittance Spectrum ◽  
Stable Phase ◽  
Cdse Thin Film ◽  
Deposited Films

Introduction: CdSe is an important II–VI semiconducting material due to its typical optical properties such as small direct band gap (1.7 eV) and a high refractive index and, thus, a major concern is focused on the investigation of optical properties of CdSe thin films which is important to promote the performances of the devices of solid -state such as SC (solar cells), thin film transistors, LED (light-emitting diodes), EBPL (electron–beam pumped lasers) and electroluminescent devices. In the present work, CdSe thin films were deposited by thermal evaporation method and the results have been analysed and presented. Materials and Methods: CdSe thin films has been deposited on glass microscopic slides as substrates of (75×25×1 mm) under room temperature using PVD technique. CdSe blended powders gets evaporated and condensed on the substrate. The film thickness (t = 100 ± 5 nm) which is measured using Michelson interferometry method. Transmission spectrum, from 200-1100 nm, are scanned using two beams UV–VIS Spectrophotometer (6850 UV/Vis. Spectrophotometer-JENWAY). The deposited films then were annealed at temperature range of (1500C to 3500C) under vacuum to have a stable phase of the material and prevent surface oxidization. Results and Discussion: A transmittance spectrum of CdSe thin film is scanned over wavelength range 200 to 1100 nm using a (6850 UV/Vis. Spectrophotometer-JENWAY) at room temperature. The transmittance percentage between the as-deposited film and the annealed films change varies from (17.0%) to (47.0%). It is clearly seen that there is a shift toward higher energy (Blue Shift) in the transmittance spectrum. As annealing temperature increased the transmittance edge is shifted to the longer wavelength (i.e., after annealing the CdSe films shows red shifts in their optical spectra). The band gap was found within the range 1.966-1.7536 eV for CdSe thin film. As annealing temperature increases, the Eg continuously decreases. Conclusions: CdSe thin films have been deposited using Physical Vapor Deposition (PVD) Technique. It is found that the transmission for as- deposited films is (17%) and increases to (47%) as annealing temperature increases. Beside this the energy gap for as- deposited CdSe film is (1.966eV) and decreased from (1.909 eV) to (1.7536eV) as the annealing temperature increases. There is a strong red shift in the optical spectrum of the annealed CdSe films. There is a gradual shift of the annealed films thin film spectra as compared of bulk CdSe films.

Structural and electrical study of BLT thin film deposited on different substrates by electron gun evaporation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
B. Abdallah ◽  
F. Nasrallah ◽  
W. Tabbky
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Ferroelectric Properties ◽  
Electron Gun ◽  
High Deposition Rate ◽  
Content Type ◽  
Glass Substrates ◽  
Evaporation Technique

Purpose The purpose of this study was to deposit Bi4Ti3O12 films by electron gun evaporation technique starting from Bi3.25La0.75Ti3O12 as a target without annealing. The films have been deposited on Si(100), on thin film buffer layer of Pt and glass substrates. X-ray diffraction (XRD) was used to analyze structure of the films, which possesses a good structure with (0010) preferred orientation. Electronic behavior of the samples has been studied. Design/methodology/approach The dependence of both the structure and quality of the BLT thin films on different substrates is studied using XRD. The electrical characteristics were determined using capacitance–voltage (C–V) and current–voltage (I–V) measurements at the frequency of 1 MHz. Optical properties of the grown films deposited on glass substrates were characterized by optical transmittance measurements (UV-Vis). Findings The XRD analysis approved the crystallographer structure of the prepared Bi4Ti3O12 films. The optical properties of deposited film (transmittance and the band gap value) are extracted by UV-Vis spectrum. Originality/value High crystalline quality Bi4Ti3O12 films have been obtained using different substrates at room temperature by means of electron gun deposition. The electrical and ferroelectric properties of thin films were studied using I–V and C–V measurements. The band gap has been found to be about 3.62 eV for the studied film deposited on glass substrate. Electron beam evaporation technique is the most interesting methods, once considering many advantages; such as its stability, reproducibility, high deposition rate and the compositions of the films are controlled.

OPTICAL PROPERTIES OF AsSeTl THIN FILMS DEPOSITED BY e-BEAM EVAPORATION TECHNIQUE

2011 ◽  
Vol 18 (01n02) ◽  
pp. 71-75 ◽  
Author(s):  
M. M. ABD EL-RAHEEM
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electron Beam ◽  
Band Gap ◽  
Optical Band Gap ◽  
Plasma Frequency ◽  
Electron Beam Evaporation ◽  
Dispersion Energy ◽  
Electron Beam Evaporation Technique ◽  
Evaporation Technique

Five compositions of the system As 25 Se 75-x Tl x (x = 12, 16, 20, 24 and 28%) have been prepared using melt quench technique. Thin films of the same thickness (200 nm) were deposited by electron beam evaporation technique. Optical and other parameters of the films have been studied. The optical band gap E op found to decrease by increasing the coordination number r and average number of bonds per atom N av and by decreasing the heat of atomization H s . Other parameters as an oscillator energy E o , dispersion energy E d and plasma frequency ω p found to be affected by changing thallium content.

Effects of Different Thermal Treatment on Optical Properties and Microstructure of ZnO Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1766-1770 ◽  
Author(s):  
Dong Ping Zhang ◽  
Ping Fan ◽  
Zhuang Hao Zheng ◽  
Li Li Ru ◽  
Jian Jun Huang ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Constant Temperature ◽  
Room Temperature ◽  
Optical Band Gap ◽  
The Other ◽  
Zno Thin Films ◽  
Zno Films ◽  
Dc Reactive Magnetron Sputtering

ZnO thin films were prepared by DC reactive magnetron sputtering at room temperature. Two of them were annealed with different modes under vacuum condition. One was annealed with constant temperature of 300°C ; the other was annealed with temperature rising step by step from room temperature to 300°C . By comparing the microstructure and optical properties of the as-grown and annealed samples, the effects of different annealing modes on ZnO films performances were revealed. The experiment results investigated that the sample annealed with constant temperature of 300°C has the high grain size and surface roughness. Both of the two annealing modes could release the intrinsic stresses to some degree. The optical band gap of the samples narrowed after annealing, and the two annealed samples have almost the same band gap. Strong green emissions are observed for all the samples, but the emission intensity decreased of the sample annealed with the temperature rising step by step compared with that of other samples.

scholarly journals Effect the Thickness on the Electrical Properties and (I-V) Character of the (CdTe) Thin Films and Find the Efficiency of Solar Cell CdTe/CdS

2018 ◽  
Vol 15 (2) ◽  
pp. 192-197
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Solar Cell ◽  
Electrical Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Annealing Temperatures ◽  
Evaporation Technique ◽  
Cdte Thin Films ◽  
Vacuum Evaporation Technique

Thin films of CdTe were prepared with thickness (500, 1000) nm on the glass substrate by vacuum evaporation technique at room temperature then treated different annealing temperatures (373,473,and 573)K for one hour. Results of the Hall Effect and the electrical conductivity of (I-V) characteristics were measured in darkness and light.at different annealing temperature results show that the thin films have ability to manufacture solar cells, and found that the efficient equal to (2.18%) for structure solar cell (Algrid / CdS / CdTe /glass/ Al) and the efficient equal to (1.12%) for structure solar cell (Algrid / CdS / CdTe /Si/ Al) with thick ness of (1000) nm with CdTe thin films at RT.

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