Conventional Thermal Evaporation Technique Research Articles

Investigations on structural and opto-electrical characterization of Ag-TCNQ (metal-organic frameworks) as complex thin films for potential device applications

The silver- (7, 7, 8, 8-tetracyanoquinodimethane (Ag-TCNQ) organometallic complex was synthesized chemically as a nano-powder and thereafter deposited as a thin film by thermal evaporation. The monoclinic, needle-like, polycrystalline structure of the Ag-TCNQ complex was analyzed employing x-ray diffraction (XRD) and a scanning electron microscope (SEM). Whereas their chemical structure and stability were explored using Fourier transformation infrared (FTIR) techniques. The findings imply a charge transfer of degree −0.5 between TCNQ° and TCNQ−, as revealed by the shift of the bands of the C≡N stretching and the (C═C-H) bond positioned at 2198 and 824 cm−1, respectively. As well as the optical properties of Ag-TCNQ thin film were studied using spectrophotometric measuring in the wavelength ranging 200 to 2500 nm. The measurement of transmittance and reflectance spectra were employed to calculate the refractive index (n), dielectric constant, absorption index (k), surface and volume energy loss functions, and optical conductivity. In the normal dispersion zone, optical characteristics such free charge carrier concentration, infinity dielectric constant (ε ∞), lattice dielectric constant (ε L), oscillator energy (Eo), and dispersion energy (Ed) were estimated. Furthermore, the optoelectronic nonlinear optical features and electronic transitions for the Ag-TCNQ thin film were assessed. Finally, these findings are promising milestones on the path to providing convincing evidence for the synthesis of stoichiometric thermally stable Ag-TCNQ thin film by conventional thermal evaporation technique that is potential to be utilized in optoelectronic devices applications.

Exploring Innovative Applications of Evaporative Cooling for High-Total-Dissolved-Solids Produced-Water Treatment

Summary This research delves into the pioneering application of evaporative cooling (EC) to address the challenge of reducing total dissolved solids (TDS) in produced water generated during hydraulic fracturing operations in the Permian Basin. In this study, we used a meticulously designed laboratory-scale EC system comprising three cooling pads, a fan, a water reservoir, and a pump. Through a systematic series of experiments, both synthetic and authentic produced-water samples were treated, shedding light on the potential of this novel approach. The EC system efficiently processed untreated produced water, circulating it through the cooling pads, all while closely monitoring crucial variables such as inlet and outlet temperatures, relative humidity, and remaining water volume, utilizing a state-of-the-art temperature and humidity meter. Control experiments were systematically conducted to probe the influence of varying salinities, achieved by introducing NaCl into distilled water, encompassing a wide range from 0 ppm to 70,000 ppm. In addition, we extended our evaluation to real produced-water samples collected from diverse regions within the Permian Basin (Delaware, Northern Midland, and Southern Midland), reflecting the system’s capability to manage high salinity and the diverse impurities inherent to oil and gas production. A comparative analysis of energy consumption was undertaken, positioning EC against conventional thermal evaporation techniques. The findings revealed a compelling insight that differences in EC efficiency between synthetic and real oilfield brines were primarily attributed to the presence of sodium (Na+) and chlorine (Cl-) contents rather than the overall TDS concentration. Across all experiments, the system consistently achieved remarkable TDS removal efficiencies, hovering around the 100% mark for both synthetic and authentic produced-water samples. Moreover, the study unveiled a significant advantage of EC, as it proved to be significantly less energy-intensive when juxtaposed with conventional thermal evaporation methods. In addition, our experiments revealed that divalent ions like CaCl2 tend to lower the treatment efficiency compared to monovalent ions, adding a crucial dimension to our understanding of EC in water treatment. The EC system demonstrated remarkable efficiency, achieving nearly 100% TDS removal in both synthetic and real samples while being significantly less energy-intensive than conventional thermal evaporation methods. This research underscores EC’s potential as an effective, sustainable, and economical solution for high-TDS water treatment, with promising applications in industrial settings. The study also draws parallels between EC and air conditioning systems, suggesting its versatility in various industrial applications.

Exploring microstructural, optical, electrical, and DFT/TD-DFT studies of boron subphthalocyanine chloride for renewable energy applications

Microstructural, optical and electrical properties of boron subphthalocyanine chloride (B- SubPc-Cl) were investigated in order to use it in energy applications. Field emission scanning microscopy (FE-SEM) was used to investigat the surface morphology and the structural nature of B- SubPc-Cl evaporated thin films. The diffuse reflectance spectra of the as-deposited and annealed B-subPc-Cl thin films were investigated based on Kubelka-Munk (K-M) function. The optical characteristics (specular transmission and reflection) were determined from the analysis the spectrophotometric measurements. Organic/inorganic B- SubPc-Cl / n-Si heterojunction diode was successfully fabricated by means of the conventional thermal evaporation technique of B- SubPc-Cl thin film onto n-Si substrates of (110) preferred orientation. The current density–voltage (J–V) of Au/ B- SubPc-Cl / n-Si/Al heterojunction device was measured at selected temperatures. The essential electrical parameters of the device such as the series resistance, ideality factor, and barrier height were estimated from the analysis of current-voltage characteristics of heterojunction diode according to the Cheung-Cheung and Norde methods. The Complex dielectric functions such as the real and imaginary dielectric parts, dielectric modulus, and electrical conductivity of Au/ B- SubPc-Cl / n-Si/Al heterojunction device were carried out with the applied frequency in the range 20 Hz to 1 MHz and selected temperatures from 298 K to 473 K. DFT/TD-DFT calculations with B3LYP/6–31 G level of theory were used to study the optimized geometry and some important parameters of B-SubPc-Cl.

Dielectric properties, Optoelectrical parameters and electronic polarizability of thermally evaporated a-Pb-Se-Ge thin films

This article is devoted to the study of various dielectric and optoelectrical parameters, besides electronic polarizability, and metallization parameter of amorphous Pb10Se90-xGex (0.0≤x≤10.0at.%) thin films. These studies are based on the calculated values of refractive and extinction coefficient. The thin films were prepared using the conventional thermal evaporation technique. All samples were previously investigated by XRD, EDX, and UV–Vis–NIR spectrophotometric measurements. Using refractive index and extinction coefficient spectra, the dielectric constant (real and imaginary parts), dissipation and quality factors are discussed. Also, many optoelectrical factors of Pb–Se-Ge films have been studied. The energy loss functions, high-frequency dielectric constant and optical carrier concentration are also deduced and studied. The plasma frequency and some other optoelectrical parameters, such as scattering time, optical mobility, and optical resistivity are studied and discussed. From the computed results it can be said that these films can be used in many optoelectronic applications, IR photodetectors, and sensors.

Study of optical parameters of sulphur doped Se-As thin films as optical materials

A conventional thermal evaporation technique has been used for thin film preparation of Se40As60−ySy (y = 0, 10, 20) chalcogenide materials. Optical characterization has been done in the wavelength range of 600–2700 nm in the thin films of above mentioned materials. Various optical parameters like refractive index, extinction coefficient, dielectric constant, dielectric loss, absorption coefficient and band gap have been calculated after the analysis of transmission spectra of the given samples. On the basis of optical parameters the optical characteristics have been discussed for Se40As60−ySy (y = 0, 10, 20) materials. Optical band gap is estimated by using Tauc’s extrapolation and is found to increase with S addition. This behavior of optical band gap is interpreted in terms of co-ordination number and chemical bond energy. The outcomes of optical characterization motivated towards to find the scope of present glassy system as optical materials.

Solar cell fabrication from semiconducting Cu3SbS3 on n-Si: Parameters evolution

Cu3SbS3 (CAS) thin films are synthesized by the conventional thermal evaporation technique. The induced effects in optical and morphological properties of these films upon the annealing process in temperature range 473–623 K are studied. X-ray diffraction (XRD) analyses reveal the amorphous nature of the as-deposited film which crystallizes in monoclinic crystal structure after annealing. The absorption coefficient, refractive index and film thickness are calculated by Swanipoel's method. The observed optical band gap (Eg) shows a decrease in its value from 1.88 to 1.61 eV after annealing which is consistent with the detected red shift of absorption edge in the transmission spectra. The fabrication and the current-voltage (J-V) characteristics of Al/n-Si/p-CAS/Ag junction at different annealing temperatures are investigated. Dark measurements reveal good rectification behavior ≈ 102. Under illumination, the best performance is achieved for annealed cell at 523 K with short circuit current (Jsc) = 6.65 mAcm2, open circuit voltage (Voc) = 0.3 V, fill factor (FF) = 30% and conversion efficiency (η) = 1.49%.

Electronic properties and photovoltaic performance of VONc-ZnO hybrid junction solar cells

In this work, we investigated the effect of the additional layer of zinc oxide (ZnO) nanoparticles to the active layer of Vanadyl-2,3-naphthalocyanine (VONc) solar cells. The two diodes were prepared using conventional thermal evaporation technique to produce ITO/VONc and ITO/ZnO/VONc heterojunctions. The change of capacitance-voltage characteristics showed that ITO/ZnO/VONc cell has a built-in potential (0.85 ± 0.01 V) higher than that for ITO/VONc cell (0.74 ± 0.02 V). The dark current-voltage characteristics were recorded for the two diodes in the temperature range of 298–393 K. The rectifier behavior of the two diodes at different temperatures has the same behavior, and ITO/ZnO/VONc cell has a higher rectification ratio. This behavior for two diodes suggests that the dominant forward conduction mechanisms found to be thermionic-emission and space charge limited current mechanisms at low and high applied voltage, respectively. The essential parameters of the diode, such as shunt resistance, series resistance, quality factor, and barrier height, were also calculated. The photovoltaic behavior of two devices has been studied with constant illumination of 80 mW/cm2 at room temperature. The efficiency of the cell is increased ten times by adding ZnO layer.

Fabrication and electrical characterization of n-1,3,3-trimethylindolino-β-naphthopyrylospiran/p-Si (organic/inorganic) heterojunction for application in photovoltaic device

1,3,3-Trimethylindolino-β-naphthopyrylospiran (SO) thin film was prepared using conventional thermal evaporation techniques onto P-Si single crystal substrate to fabricate n-SO/P-Si heterojunction. The dark current–voltage (I–V) characterization and its temperature dependence in forward and reverse bias were investigated. This characteristic suggests that the forward conduction was dominated by thermionic-emission and space-charge-limited current (SCLC) mechanisms at low, (Vf ≤ 0.2 V), and high, (0.5 ≤ Vf ≤ 1.5 V), voltage, respectively. In addition, the current-voltage characteristics allow us to extract some characteristic important parameters of diode such as the series resistance, Rs, shunt resistance, Rsh, quality factor, n, and the barrier height, φ. Furthermore, the dark room temperature C–V characteristics was investigated to estimate the values of the junction built-in potential at 1 MHz and the charge carrier concentration. In addition, the device showed strong photovoltaic characteristics under constant illumination of 5 mW/cm2 at room temperature, with parameter values 0.6 V, 56.6 mA/cm2, 0.32% and ∼1.2% for open circuit voltage, Voc, the short circuit current density, Jsc, the fill factor, FF, and conversion efficiency, η, respectively.

AC impedance spectroscopy on Al/p-Si/ZnTPyP/Au heterojunction for hybrid solar cell applications

A p-Silicon/Zn-tetra pyridyl-porphyrin (ZnTPyP) heterojunction was fabricated by forming a ZnTPyP layer on a p-type Si single crystal substrate using a conventional thermal evaporation technique. Complex impedance measurements of the Al/p-Si/ZnTPyP/Au heterojunction were carried out at applied AC-voltage range from 0.2 V to 1 V, temperature range from 303 K to 353 K and over the frequency range from 100HZ to 2 MHz. Impedance spectra of the heterojunction under the standard illumination ranged from 0 to 40 mW/cm2 were reported and analysed.

Structural , and Photochromic Properties of Thermally Evaporated E-3-(Adamantan -2-Ylidene)-4-[1 - (2,5-Dimethy-3furyl) Ethyldene] Dihydro-2,5-Furandione Thin Films

Structural , and Photochromic Properties of Thermally Evaporated E-3-(Adamantan -2-Ylidene)-4-[1 - (2,5-Dimethy-3furyl) Ethyldene] Dihydro-2,5-Furandione Thin Films M. M. El- Nahass, A. M. A. El-Barry Abstract Thin Films of E-3-(Adamantan -2-Ylidene)-4-[1 - (2,5-dimethy-3furyl) ethyldene] dihydro-2,5- Furandione compound were prepared by conventional thermal evaporation technique. X-ray diffraction patterns indicated that the compound in the powder form has a polycrystalline nature with momoclinic structure . The Miller indices for the powder were calculated for the first time using Check,s cell program . SEM indicated the short range order of the films. FTIR indicated the consistent of both the powder and the as-deposited thin films. The films were irradiated with UV light (360 nm) for different times from 1 to 11 min. The color of the films converted to saturated rose color after an exposure time ≅ 6 min . The photobleaching time was found to be 13.5 min under the effect of Vis light, using a white light. This behaviour deduced the photochromic effect of the compound which has been explained according to the presence of the open cycle E-isomer which converted to the closed C-isomer under the effect of the UV-light. The refractive index, n, and the absorption index, k, and the the parameters of molar extinction coefficient (εmolar) were evaluated for both as deposited and the colored films. The concentration of the coloring centers through the thin films were found to be ~ 1.18 x10 10 /cm3 . The studying of the dispersion spectra indicated abnormal behaviour companied with plasma frequency. Finally; The analysis of the absorption coefficient revealed the present of direct optical gap with 3.17 ±0.006 eV for the deposited films ,which decreased to 2.48 ±0.003 eV for the colored films . Full Text: PDF DOI: 10.15640/jns.v5n1a2

Osmotic and membrane distillation for the concentration of tomato juice: Effects on quality and safety characteristics

Abstract The aim of this study was to evaluate the utilization of osmotic distillation, membrane distillation, and coupled operation of these systems as an alternative to the conventional thermal evaporation (CTE) technique for the concentration of tomato juice. Some physicochemical characteristics of the products obtained by different techniques were determined. The samples concentrated by membrane systems were more advantageous by means of many parameters investigated, especially for color, hydroxymethylfurfural (HMF) and furan formation. HMF and furan contents were increased up to three to four times after CTE while there was no statistical change after membrane concentrations. Ascorbic acid and dehydroascorbic acid levels were decreased significantly after all concentration operations. Nonetheless, as total vitamin C content, membrane systems were more advantageous compared to CTE. Sensorial evaluation also showed that, except consistence, products obtained by membrane techniques gained higher scores than thermally concentrated products. Industrial Relevance The quality of tomato paste is dependent on process conditions used to convert the tomato pulp into paste. Conventional thermal evaporation may result in the deterioration of product quality by damaging heat sensitive tomato juice components as well as inducing color changes. Moreover, some mutagenic and carcinogenic compounds such as furan and HMF may be formed. Concentration of tomato juice using membrane systems can be proposed as the promising alternative to the CTE since most of the characteristics, especially color, are preserved, and HMF and furan formations are reduced significantly by these processes.

Fabrication, electrical and photovoltaic characteristics of perylene-66 based diodes (comparative study)

In this work, two diodes of Au/perylene-66/p-Si/Al and Au/perylene-66/TiO2/p-Si/Al were prepared by conventional thermal evaporation technique. Temperature-dependence of the electrical characteristics of the two diodes in the temperature range of 303–373K was investigated. Barrier height and ideality factor were determined and studied as a function of temperature. The barrier height was found to increase and the ideality factor decreases by increasing temperature which may be attributed to barrier height inhomogeneities. Variation of the capacitance–voltage characteristics (i.e. 1/C2–V dependence) shows a straight line fit which support the abrupt diode type. Most of diode parameters of Au/perylene-66/TiO2/p-Si/Al is found to be high as compared to Au/perylene-66/p-Si/Al due to the effect of TiO2insertion. The photovoltaic characteristics of the two diodes were investigated under illumination to study the applicability for optoelectronic applications.

Structural characterization and optical properties of thermally evaporated AgSb0.75In0.25Se2 thin films

Polycrystalline AgSb0.75In0.25Se2 ingot material was prepared by direct fusion of the mixtures of their constituent elements in vacuum-sealed silica tube. The structural characterization of the prepared ingot material was investigated using X-ray diffraction technique. Thin films of the reveiously prepared bulk material were deposited at room temperature using conventional thermal evaporation technique. The structural characterization of the deposited films performed using X-ray diffraction and transmission electron microscope, showed that the as-deposited film has an amorphous phase, whereas those annealed at temperatures Ta≥453K are crystalline. The chemical composition of the deposited films was examined using energy dispersive X-ray analysis. The optical properties of the amorphous and crystalline films have been determined from the transmission spectra using envelope method. The refractive index is adequately described in terms of the single-effective-oscillator model proposed by Wemple–DiDomenico. The optical band gap of the amorphous and crystalline films has been determined from the analysis of the optical absorption coefficient.

Design and electrical characterization of Au/Anthracene/p-Si/Al organic/inorganic heterojunction

Hybrid organic/inorganic heterojunction of nanocrystalline Anthracene and p-Si was fabricated by using a conventional thermal evaporation technique. The crystal and molecular structure of the Anthracene thin films were analyzed by means of X-ray diffraction (XRD), and Fourier Transformation-Infra Red (FT-IR) spectroscopy. The morphologies of the Anthracene/p-Si were investigated by scanning electron microscopy (SEM). The dark current–voltage (I–V) characteristics of Au/Anthracene/p-Si/Al heterojunction were investigated at room temperature (293K). The calculated series resistance and the shunt resistance of the device were found to be 440Ω and 1.47MΩ, respectively. The Cheung–Cheung and Norde’s models were used to investigate and determine the heterojunction parameters. The ideality factor and barrier height values of the Au/Anthracene/p-Si/Al diode were obtained to be 1.1 and 0.464eV, respectively. The dependence of capacitance–voltage (C−2–V) for the device Anthracene/p-Si was found to be almost linear. Essential junction parameters and performance of heterojunction established a photovoltaic behavior with an open circuit voltage (Voc) 0.382V, short circuit photocurrent (ISC) 0.72mA and power conversion efficiency (η) of 4.65%.

Electrical and photovoltaic properties of CuTPP/p-Si organicinorganic hybrid hetrojunction

Thin films of 5,10,15,20-Tetraphenyl-21H,23H-porphine copper(II), CuTPP were prepared by conventional thermal evaporation technique on p-Si substrates to form CuTPP/p-Si organic-inorganic hybrid hetrojunction. The temperature-dependence of the electrical characteristics of the CuTPP/p-Si heterojunction in the temperature range of 298-353 K was studied. The barrier height and ideality factor of the heterojunction were determined as a function of temperature. It is noticed that the bias barrier height b increases and the ideality factor m decreases by increasing the temperature. Such behavior can be attributed to barrier inhomogeneities by assuming a high mismatch in CuTPP /p-Si interface. The value of series (Rs) and shunt (Rsh) resistances were determined using junction resistance and found to be a strongly temperature. Variation of 1/C 2 with voltage shows a straight line at high frequency (1 MHz) indicating the formation of barrier between CuTPP and p-Si and the potential barrier height is about 0.92 eV at 298 K. The photovoltaic properties of CuTPP /p-Si heterojunction were investigated under illumination and the main important parameters such as open circuit voltage, Voc, and short circuit current,Isc, were found to be 0.289 V and 0.03 A,respectively..

The Effect of Changing the Vapor Flux on Physical Properties of Nanocrystaline CdTe Thin Film, Prepared by Thermal Evaporation Method

In the present investigation, seven Cadmium Telluride (CdTe) thin films with thickness of 350nm have been prepared by vacuum thermal evaporation technique. One of them was deposited by conventional vacuum thermal evaporation technique, while six others were deposited with applying a novel vapor flow controlling system. Placing this equipment in the way of vapor flux from the source to the substrate cut the depositing flux of vapor periodically and can change the way of vapor flux. It led to considerable change of optical properties, nanocrystalline structure, and also stochiometery of the thin films. All the samples showed nanocrystalline structure. A considerable increase in absorption coefficient was observed at 520nm wavelength of light, from 5.5 ×104cm-1for the sample prepared with conventional vacuum thermal evaporation technique to 9.8×104cm-1for a sample which prepared by applying mentioned equipment. The most considerable change in the bandgap, grain size and Te/Cd ratio were 1.54 eV to 1.66 eV, 40nm to 15nm, and 56/44 to 60/40 respectively. The optical parameters such as absorption coefficient, bandgap, refractive index, and structural parameters such as texture coefficient, preferential orientation factor and crystallite size of samples were obtained. Also EDAX and FESEM result of samples were compared with each other in this study.

Characterization and photovoltaic performance of organic device based on CoMTPP/p-Si heterojunction

Hybrid organic/inorganic heterojunction of nanocrystalline 5,10,15,20-Tetrakis(4-methoxyphenyl)-21H,23H-porphine cobalt(II), (CoMTPP) and p-Si was fabricated by using the conventional thermal evaporation technique. The morphologies of the CoMTPP/p-Si were investigated by scanning electron microscopy (SEM). The dark current–voltage (I–V) characteristics of Au/p-CoMTPP/p-Si/Al heterojunction diode measured at different temperatures ranging from 298 to 423K have been investigated. Analytical approaches involving the thermionic emission and space charge limited currents (SCLC) were used to explain the I–V behavior in the forward bias. On the other hand, the carrier generation–recombination process limits the reverse current. The dependence of capacitance–voltage (C−2–V) for the device CoMTPP/p-Si was found to be almost linear which indicates that the junction behavior is abrupt nature and then the essential junction parameters were obtained. The performance of heterojunction showed a photovoltaic behavior with an open circuit voltage, Voc, of 0.283V, short circuit photocurrent ISC, of 0.433mA and power conversion efficiency, η of 3.6%.

Electrical transport mechanisms and photovoltaic behavior of 2-(2-furanylmethylene) propanedinitrile/p-Si heterojunction

Au/2-(2-furanylmethylene) propanedinitrile/p-Si heterojunction was fabricated using conventional thermal evaporation technique. Current density–voltage (J–V) characteristics of the heterojunction were investigated at different temperatures. Tunneling conduction mechanism in the lower voltage range was identified from the forward bias (J–V) characteristics. The calculated value of the change of built-in voltage with respect to the absolute temperature is (−1.88 × 10−3 V K−1). At higher voltages, a space charge limited current (SCLC) mechanism controlled by an exponential trapping distribution above the valence band edge was observed. The total concentration of traps was found to be 8.077 × 1021 m−3. Under reverse bias, the conduction mechanism is due to thermally generated carriers in the lower voltage range and the Poole–Frenkel effect is observed in the higher voltage range. The heterojunction showed a photovoltaic behavior under illumination with an open-circuit voltage of 0.19 V and a short-circuit current density of 102.7 mA m−2.

Compositional effects on the optical properties of Gex Sb40−x Se60 thin films

Gex Sb40−x Se60 (x = 0, 2.42 and 23.41 at.%) thin chalcogenide films were deposited on glass and quartz substrates by the conventional thermal evaporation technique at 300 K. The chemical composition of the bulk material and as-deposited films were determined by energy dispersive analysis X-ray spectrometry (EDAX). X-ray diffraction pattern (XRD) of Gex Sb40−x Se60 (x = 0, 2.42 and 23.41 at.%) thin films indicates that they have amorphous structure. The optical transmission and reflection spectra were measured in the range of 500 to 2500 nm. The optical absorption coefficient spectra were studied for deposited samples. It is observed that the optical absorption edge shift to higher energy range, as the germanium content, x, increases in the film. The type of electronic transition, responsible for the optical properties, is indirect allowed transition. It is found that the optical band gap increases as the Ge content increases.The average coordination number (Nc) in Gex Sb40−x Se60 films increases, but the number of chalcogenide atoms remains constant. The number of Ge – Se bonds and the average bond energy of the system increase with the increase of the average coordination number. The optical band gap, Eg, increases with the increase of the average coordination number, (Nc). Also the energy gap, E04, is discussed in terms of its relation to the chemical composition. The dispersion of the refractive index (n) is discussed in terms of the Single Oscillator Model (SOM) (Wimple – Didomenico model). The single oscillator energy (E0), the dispersion energy (Ed) and the optical dielectric constant (ɛ∞) are also estimated.

Electrical conductivity and dielectric properties of cadmium thiogallate CdGa2S4 thin films

Cadmium thiogallate CdGa2S4 thin films were prepared using a conventional thermal evaporation technique. The dark electrical resistivity calculations were carried out at different elevated temperatures in the range 303–423 K and in thickness range 235–457 nm. The ac conductivity and dielectric properties of CdGa2S4 film with thickness 457 nm has been studied as a function of temperature in the range from 303 to 383 K and in frequency range from 174 Hz to 1.4 MHz. The experimental results indicate that σac(ω) is proportional to ωs and s ranges from 0.674 to 0.804. It was found that s increases by increasing temperature. The results obtained are discussed in terms of the non overlapping small polaron tunneling model. The dielectric constant (e′) and dielectric loss (e″) were found to be decreased by increasing frequency and increased by increasing temperature. The maximum barrier height (Wm) was estimated from the analysis of the dielectric loss (e″) according to Giuntini’s equation. Its value for the as-deposited films was found to be 0.294 eV.