Study of Conduction Mechanism in Amorphous Se85-xTe15Bix Thin Films

2010 ◽  
Vol 303-304 ◽  
pp. 1-5 ◽  
Author(s):  
Ambika Sharma ◽  
P.B. Barman
Keyword(s):  
Thin Films ◽  
Conduction Mechanism ◽  
Low Voltage ◽  
Melt Quenching ◽  
Voltage Range ◽  
Glassy Alloys ◽  
Ohmic Behavior ◽  
Linear Behavior ◽  
Evaporation Technique ◽  
Minimum Resistance

Bulk samples of Se85-xTe15Bix (where x = 0, 1, 2, 3, 4, 5) glassy alloys are prepared by melt quenching technique. Thin films of the corresponding bulk samples are prepared by vacuum evaporation technique. I-V characteristics of Se85-xTe15Bix thin films are studied using Keithley 6487 picoammeter. Linear behavior of current has been observed at low voltage range and current is found to deviate from linearity i.e. tend towards non-Ohmic behavior in the higher voltage range. The value of resistance is also calculated in three different voltage ranges (0-90 V), (110-200 V) and (220-300 V) for the films under consideration. Maximum resistance has been observed for x = 1 and minimum resistance for x = 5. The conduction mechanism is discussed qualitatively and it is found to be of Poole Frenkel type for higher voltage range.

scholarly journals I-V measurements of Ge-Se-Sn chalcogenide glassy alloys

2015 ◽  
Vol 9 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Vandana Kumari ◽  
Anusaiya Kaswan ◽  
Dinesh Patidar ◽  
Narendra Saxena ◽  
Kananbala Sharma
Keyword(s):  
Elevated Temperatures ◽  
Low Voltage ◽  
Constant Load ◽  
Dc Conductivity ◽  
Voltage Range ◽  
Glassy Alloys ◽  
Current Voltage ◽  
Maximum Current ◽  
Current Voltage Characteristics ◽  
Minimum Resistance

Current-voltage characteristics and DC electrical conductivity were studied for Ge30-xSe70Snx (x = 8, 11, 14, 17 and 20) glassy thin pellets of diameter 12mm and thickness 1mm prepared under a constant load of 5 tons using a well-known melt quenching technique in bulk as a function of composition. The I-V characteristics were recorded at room temperature as well as elevated temperatures up to 300?C. The experimental data suggests that glass containing 20 at.% of Sn has the minimum resistance allowing maximum current through the sample as compared to other counterparts of the series. Therefore, DC conductivity is found to increase with increasing Sn concentration. Composition dependence of DC conductivity is discussed in terms of the bonding between Se and Sn. Plots between ln I and V1/2 provide linear relationship for both low and high voltage range. These results have been explained through the Pool-Frenkel mechanism. The I-V characteristics show ohmic behaviour in the low voltage range and this behaviour turns to non-ohmic from ohmic in the higher voltage range due to voltage induced temperature effects.

Investigation of Electrical Properties in Chalcogenide Thin Film According to Wave Length

2007 ◽  
Vol 31 ◽  
pp. 135-137
Author(s):  
H. Choi ◽  
H.K. Kim ◽  
Y.W. Koo ◽  
K.H. Nam ◽  
S.M. Koo ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Wave Length ◽  
Potential Candidate ◽  
Melt Quenching ◽  
Programmable Metallization Cell ◽  
Glassy Alloys ◽  
Electrochemical Control ◽  
Evaporation Technique ◽  
Chalcogenide Thin Film

Programmable metallization cell (PMC) memory is based on the electrochemical control of nanoscale quantities of metal in thin films of solid electrolyte. We investigate the nature of thin films formed by the photo-dissolution of Ag into Ge-Se-Te glasses for use in programmable metallization cell devices. Glassy alloys of a-Ge25Se75-xTex(x = 0, 25) are prepared by well known melt-quenching technique. Thin films of a-Ge25Se75-xTex(x = 0, 25) glassy alloys are evaporated by vacuum evaporation technique at ~10-6 torr on glass substrate at room temperature. Optical properties in this study concerns photo-diffusion of Ag on Ag-doped Ge-Se-Te electrolytes. With these promising properties, the composition a-Ge25Se75-xTex(x = 0, 25) is recommended as a potential candidate for PMC-RAM.

ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF A-Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) THIN FILMS

2013 ◽  
Vol 22 ◽  
pp. 439-451
Author(s):  
AMBIKA SHARMA ◽  
KUMARI ANSHU ◽  
PREETI YADAV
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Life Time ◽  
Defect States ◽  
Temperature Dependent ◽  
Photoelectrical Properties ◽  
Glassy Alloys ◽  
Localized State ◽  
Evaporation Technique ◽  
Density Of Defect States

Bulk samples of Te-rich Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) glassy alloys are prepared by melt quenching technique. The thin films of the bulk samples are deposited by using vacuum evaporation technique for their electrical and photoelectrical measurements. Keithley 6487 picoammeter has been used to study the electrical and photoelectrical characteristics of Ge20Te80-XBix thin films kept in vacuum. Temperature dependent dark and photoconductivity is studied in the temperature range 300-360 K and voltage V = 80V. Photoconductivity with intensity at room temperature follows a power law where power γ lies near to 0.5, suggesting that the recombination is bimolecular in nature. The density of defect states and photosensitivity are found to follow an opposite trend with each other. The differential life time is determined from the rise and decay of photocurrent w.r.t. time. The dispersion parameter and localized state distribution parameter are estimated from decay curves and reported for the studied composition.

scholarly journals A Comparative Study of the Semiconductor Behavior of Organic Thin Films: TCNQ-Doped Cobalt Phthalocyanine and Cobalt Octaethylporphyrin

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5800
Author(s):  
María Elena Sánchez-Vergara ◽  
Citlalli Rios ◽  
Omar Jiménez-Sandoval ◽  
Roberto Salcedo
Keyword(s):  
Thin Films ◽  
Organic Semiconductors ◽  
Indium Tin Oxide ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Cobalt Phthalocyanine ◽  
Dft Methods ◽  
Ohmic Behavior ◽  
Semiconductor Thin Films ◽  
Evaporation Technique

The structure formed by cobalt phthalocyanine (CoPc) and cobalt octaethylporphyrin (CoOEP) with electron-acceptor tetracyano-π-quinodimethane (TCNQ), was studied by Density Functional Theory (DFT) methods. According to theoretical calculations, both cobalt systems can establish dispersion forces related to TCNQ and also in both cases the link between them is built by means of hydrogen bonds. Based on the results of these DFT calculations, we developed experimental work: the organic semiconductors were doped, and the thermal evaporation technique was used to prepare semiconductor thin films of such compounds. The structure of the films was studied by FTIR and Raman spectroscopy. The optical properties of the CoPc-TCNQ and CoOEP-TCNQ films were investigated by means of UV-Vis measurements. The results obtained were used to estimate the type of transitions and the optical bandgap. The results were compared to the previously calculated theoretical bandgap. The CoOEP-TCNQ film presented the smallest theoretical and experimental bandgap. Finally, the electrical properties of the organic semiconductors were evaluated from a PET (polyethylene terephthalate)/indium tin oxide (ITO)/cobalt macrocycle-TCNQ/silver (Ag) device we prepared. The CoOEP-TCNQ-based device showed an ohmic behavior. The device manufactured from CoPc-TCNQ also showed an ohmic behavior at low voltages, but significantly changed to SCLC (space-charge limited conductivity) at high voltage values.

Annealing Effect on the Optical Properties of Multi Walled Carbon Nano Tube Doped Cu5Se75Ge10In10 Thin Films Prepared by Thermal Evaporation Method

2020 ◽  
Vol 12 (1) ◽  
pp. 78-82
Author(s):  
Surabhi Mishra ◽  
Priyanka Jaiswal ◽  
Pooja Lohia ◽  
D. K. Dwivedi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Bulk Sample ◽  
Optical Data ◽  
Thermal Evaporation Method ◽  
Glassy Alloys ◽  
Different Temperatures ◽  
Evaporation Technique

The optical properties of as prepared and annealed [(Cu5Se75Ge10In10)99 (CNT)1] thin films deposited with thermal evaporation technique has been discussed as a function of photon energy in wavelength range 300–900 nm in present paper. The bulk sample of as prepared glassy alloys were developed using the melt quench technique. Thin films of prepared glassy alloys were deposited on a glass substrate with thermal evaporation unit at room temperature at base pressure of ∼10–5 Pa. The films were annealed at two different temperatures between glass transition temperature and crystallization temperatures. Analysis of the optical data shows that optical bandgap decreases with increasing annealing temperature while extinction coefficient, absorption coefficient and transmission shows increasing behaviour with increase in annealing temperature.

scholarly journals Analysis of AC-Conductivity in Chalcogenide Ge10Se20 Bi80Thin Film

2016 ◽  
Vol 13 (2) ◽  
pp. 110-115 ◽  
Author(s):  
Shiveom Srivastav
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Conduction Mechanism ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Melt Quenching ◽  
Thermal Evaporation Method ◽  
Correlated Barrier Hopping ◽  
Dominant Conduction Mechanism

The alloy Ge10Se20 Bi80 has been prepared. Thin films of Ge10Se20 Bi80 has been prepared via a thermal evaporation method (melt quenching technique) with 3000A thickness, and rate of deposition (4.1) A/sec at pressure 2x10-5 Torr. The A.C electrical conductivity of a- thin films Ge10Se20 Bi80 has been studied as a function of frequency for annealing temperature within the range (423-623) K, the deduced exponent s values, was found to decrease with increasing of annealing temperature through the frequency of the range (102-106) Hz. It was found that, the correlated barrier hopping (CBH) is the dominant conduction mechanism. Values of dielectric constant ε1 and dielectric loss ε2 were found to decrease with frequency and increase with temperature. The activation energies have been calculated for the annealed thin films.

Structural and optical properties of Tin Oxide and Indium doped SnO2 thin films deposited by thermal evaporation technique

2016 ◽  
Vol 12 (3) ◽  
pp. 4394-4399
Author(s):  
Sura Ali Noaman ◽  
Rashid Owaid Kadhim ◽  
Saleem Azara Hussain
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Tin Oxide ◽  
Thermal Evaporation ◽  
Pure Sno2 ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Evaporation Technique ◽  
Sno2 Thin Films

Tin Oxide and Indium doped Tin Oxide (SnO2:In) thin films were deposited on glass and Silicon  substrates  by  thermal evaporation technique.  X-ray diffraction pattern of  pure SnO2 and SnO2:In thin films annealed at 650oC and the results showed  that the structure have tetragonal phase with preferred orientation in (110) plane. AFM studies showed an inhibition of grain growth with increase in indium concentration. SEM studies of pure  SnO2 and  Indium doped tin oxide (SnO2:In) ) thin films showed that the films with regular distribution of particles and they have spherical shape.  Optical properties such as  Transmission , optical band-gap have been measured and calculated.

Structural, optical and electrical properties of thermal evaporated nano sized In2Te3 thin films

2018 ◽  
Vol 1 (1) ◽  
pp. 21-25
Author(s):  
R Revathi ◽  
R Karunathan
Keyword(s):  
Thin Films ◽  
Negative Temperature Coefficient ◽  
Thermal Evaporation ◽  
Structural Parameters ◽  
Negative Temperature ◽  
Resistivity Measurements ◽  
Allowed Transition ◽  
Evaporation Technique ◽  
Indium Telluride ◽  
Made In

Indium Telluride thin films were prepared by thermal evaporation technique. Films were annealed at 573K under vacuum for an hour. Both as-deposited and annealed films were used for characterization. The structural parameters were discussed on the basis of annealing effect for a film of thickness 1500 Å. Optical analysis was carried out on films of different thicknesses for both as - deposited and annealed samples. Both the as- deposited and annealed films exhibit direct and allowed transition. Electrical resistivity measurements were made in the temperature range of 303-473 K using Four-probe method. The calculated resistivity value is of the order of 10-6 ohm meter. The activation energy value decreases with increasing film thickness. The negative temperature coefficient indicates the semiconducting nature of the film.

An optimized process for fabrication of SrBi2Ta2O9 thin films using a novel chemical solution deposition technique

1999 ◽  
Vol 14 (11) ◽  
pp. 4395-4401 ◽  
Author(s):  
Seung-Hyun Kim ◽  
D. J. Kim ◽  
K. M. Lee ◽  
M. Park ◽  
A. I. Kingon ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Low Voltage ◽  
Ferroelectric Properties ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Chemical Solution Deposition Method ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Voltage Saturation

Ferroelectric SrBi2Ta2O9 (SBT) thin films on Pt/ZrO2/SiO2/Si were successfully prepared by using an alkanolamine-modified chemical solution deposition method. It was observed that alkanolamine provided stability to the SBT solution by retarding the hydrolysis and condensation rates. The crystallinity and the microstructure of the SBT thin films improved with increasing annealing temperature and were strongly correlated with the ferroelectric properties of the SBT thin films. The films annealed at 800 °C exhibited low leakage current density, low voltage saturation, high remanent polarization, and good fatigue characteristics at least up to 1010 switching cycles, indicating favorable behavior for memory applications.

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