Thickness dependence of AC conductivity in TlSe thin films

2019 ◽  
Vol 97 (11) ◽  
pp. 1182-1184
Author(s):  
Ugur Saglam ◽  
Sahin Yakut ◽  
Binnur Karabak ◽  
Deniz Bozoglu
Keyword(s):  
Thin Films ◽  
Ac Conductivity ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
High Vacuum ◽  
Low Frequency ◽  
Covalent Bond ◽  
Tetragonal Symmetry ◽  
Glass Substrates ◽  
A Chain

Thalium selenide (TlSe), which has a lattice with tetragonal symmetry, is a member of the A3B6 semiconductor group. The structure of TlSe is defined as chains where atoms inside are bonded with an ionic-covalent bond. TlSe thin films were deposited by thermal evaporation under a high vacuum on glass substrates. The structure of TlSe thin films is amorphous with a tetragonal structure. The AC conductivity measurements were operated via the measurements of capacitance and dielectric dissipation (tanδ) at room temperature. AC conductivity values change between 10−11 and 10−6 S/cm at the low-frequency side with decreasing thickness. Two different conduction regions were observed with increasing frequency. The region observed at the low-frequency side can be attributed to the motion of a chain-like part of the lattice, while the region observed at the high-frequency side can be attributed to side groups.

The effect of dielectric top lids on materials processing in a low frequency inductively coupled plasma (LF-ICP) reactor

2014 ◽  
Vol 32 ◽  
pp. 1460340
Author(s):  
J. W. M. Lim ◽  
C. S. Chan ◽  
L. Xu ◽  
S. Xu
Keyword(s):  
Thin Films ◽  
Inductively Coupled Plasma ◽  
Plasma Reactor ◽  
High Vacuum ◽  
Low Frequency ◽  
Optical Emission ◽  
Good Alternative ◽  
Plasma Sources ◽  
Inductively Coupled ◽  
Glass Substrates

The advent of the plasma revolution began in the 1970's with the exploitation of plasma sources for anisotropic etching and processing of materials. In recent years, plasma processing has gained popularity, with research institutions adopting projects in the field and industries implementing dry processing in their production lines. The advantages of utilizing plasma sources would be uniform processing over a large exposed surface area, and the reduction of toxic emissions. This leads to reduced costs borne by manufacturers which could be passed down as consumer savings, and a reduction in negative environmental impacts. Yet, one constraint that plagues the industry would be the control of contaminants in a plasma reactor which becomes evident when reactions are conducted in a clean vacuum environment. In this work, amorphous silicon (a-Si) thin films were grown on glass substrates in a low frequency inductively coupled plasma (LF-ICP) reactor with a top lid made of quartz. Even though the chamber was kept at high vacuum (~10−4 Pa), it was evident through secondary ion mass spectroscopy (SIMS) and Fourier-transform infra-red spectroscopy (FTIR) that oxygen contaminants were present. With the aid of optical emission spectroscopy (OES) the contaminant species were identified. The design of the LF-ICP reactor was then modified to incorporate an Alumina ( Al2O3 ) lid. Results indicate that there were reduced amounts of contaminants present in the reactor, and that an added benefit of increased power transfer to the plasma, improving deposition rate of thin films was realized. The results of this study is conclusive in showing that Al2O3 is a good alternative as a top-lid of an LF-ICP reactor, and offers industries a solution in improving quality and rate of growth of thin films.

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 Effect of thickness on structural properties of BixSb2-xTe3 thin films

2019 ◽  
Vol 17 (41) ◽  
pp. 15-28
Author(s):  
Hussain. M. Selman
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Average Surface Roughness ◽  
X Ray Diffraction ◽  
Polycrystalline Structure ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates ◽  
Different Thickness

BixSb2-xTe3 alloys with different ratios of Bi (x=0, 0.1, 0.3, 0.5, and 2) have been prepared, Thin films of these alloys were prepared using thermal evaporation method under vacuum of 10-5 Torr on glass substrates at room temperature with different deposition rate (0.16, 0.5, 0.83) nm/sec for thickness (100, 300, 500) respectively. The X–ray diffraction measurements for BixSb2-xTe3 bulk and thin films indicate the polycrystalline structure with a strong intensity of peak of plane (015) preferred orientation with additional peaks, (0015) and (1010 ) reflections planes, which is meaning that all films present a very good texture along the (015) plane axis at different intensities for each thin film for different thickness. AFM measurements for the thin films of BixSb2-xTe3, show that the grain size and the average surface roughness decreases with increasing of the percentage Bi for different thickness.

scholarly journals Study the effect of thickness and annealing temperature on the Electrical Properties of CdTe thin Films

2008 ◽  
Vol 5 (3) ◽  
pp. 449-453
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Conductivity Measurements ◽  
Annealing Temperature Increase ◽  
Glass Substrates ◽  
Cdte Thin Films ◽  
Different Thickness

The electrical properties of polycrystalline cadmium telluride thin films of different thickness (200,300,400)nm deposited by thermal evaporation onto glass substrates at room temperature and treated at different annealing temperature (373, 423, 473) K are reported. Conductivity measurements have been showed that the conductivity increases from 5.69X10-5 to 0.0011, 0.0001 (?.cm)-1 when the film thickness and annealing temperature increase respectively. This increasing in ?d.c due to increasing the carrier concentration which result from the excess free Te in these films.

Microstructural and Optical Properties of SnO Thin Film by Thermal Evaporation

2013 ◽  
Vol 795 ◽  
pp. 558-562
Author(s):  
Lee Siang Chuah ◽  
Z. Mohamed ◽  
Zainuriah Hassan
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Hole Concentration ◽  
Hexagonal Wurtzite Structure ◽  
Thermal Evaporation Method ◽  
Sem Image ◽  
Glass Substrates ◽  
Xrd Patterns ◽  
P Type

In this work, we present results about the preparation and characterization of stannous oxide (SnO) thin films. SnO thin films were obtained via thermal evaporation method from SnO2powder as source material. These thin films were successfully deposited onto well cleaned glass substrates by thermal evaporation technique. The as deposited thin films were of thickness of 2500 Å and film were post-deposition annealed in air ambient at 400°C for 20 min and 40 min, respectively in a furnace. As-deposited films are highly conductive andptype. The best p-type SnO film annealed at 400 °C for 40 min shows a resistivity of 1.05 Ω·cm and a relatively high hole concentration of 2 × 1017cm3at room temperature. The X-ray diffraction (XRD) patterns of annealed films exhibit a polycrystalline hexagonal wurtzite structure without preferred orientation. The scanning electron microscopy (SEM) image shows the presence of uniformly dispersed spherical in shaped SnO particles. The mean grain sizes (diameter) are calculated to be about 80 and 100 nm for the p-type SnO films prepared at 400 °C for 20 min, and 40 min, respectively. Room temperature photoluminescence (PL) spectra of the SnO film exhibit two emission bands, around the wavelength of 300 nm and 450 nm. All spectra were measured at room temperature.

TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

1993 ◽  
Vol 51 ◽  
pp. 1118-1119
Author(s):  
Pamela F. Lloyd ◽  
Scott D. Walck
Keyword(s):  
Thin Films ◽  
Sample Preparation ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Ultra High Vacuum ◽  
Wear Testing ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

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.

Microstructural Study of Thin Films CuFe Obtained by Thermal Evaporation of Nanostructured Milled Powder

2017 ◽  
Vol 47 ◽  
pp. 71-78
Author(s):  
H. Mechri ◽  
Ahmed Haddad ◽  
M. Zergoug ◽  
Mohammed Azzaz
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Physical Vapor Deposition ◽  
Thermal Evaporation ◽  
Supersaturated Solid Solution ◽  
Milled Powder ◽  
Mechanically Alloyed ◽  
Glass Substrates ◽  
Milling Duration ◽  
Tungsten Boat

Commercial copper and iron powders were used as starting materials. These powders were mechanically alloyed to obtain Cu(100-x) Fex supersaturated mixture. The milling duration was chosen in such a way as to obtain a nanostructured mixture and to form a supersaturated solid solution of CuFe; the powder mixture was used to deposit CuFe on a glass substrate. The elaboration of our films has been carried out using thermal evaporation process (physical vapor deposition) under 1 × 10-6 mbar vacuum from an electrically heated tungsten boat, using the supersaturated solid solution Cu(100-x) Fex powder obtained by mechanical alloying. The films deposition has been done on glass substrates. In this study, we present the composition effect on the structural and magnetic proprieties of Cu(100-x) Fex powder and thin films. The chemical composition, structural and magnetic proprieties of milled powders and thin films were examined by SEM, TEM, XRD, XRF and VSM.

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.

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