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1
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Influence of Substrate Local Heating on Morphology of~Al and Al_2O_3 Nanofilms

100%
Reszka K., Szczypiński M., Pomorska M.
Acta Physica Polonica A
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2011
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vol. 120
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issue 1
177-180
EN
Experimental investigations presented in this work were focused on the execution of a carousel system with its usability for step-by-step revolutions and the mechanism for clamping the heater, which made it possible to heat substrates individually within the range from 25°C to 300°C. This system was used for depositing the metallic Al films by the magnetron sputtering method on foil made of FeCrAl steel, which found application in the production of metallic catalytic reactors. It was found that in the case of not-heated foil the polycrystalline continuous Al film, which is separated from steel by an amorphous oxide nanofilm obtained spontaneously under influence of weather conditions, was created. The deposition of aluminium on foil heated to the temperature of 300°C caused the film marked by fine grains integrated with small forces to be formed. These differences had an influence on the morphology of the oxide films.
2
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Corrosion Behavior of Nitride and Cr-Al-N Coatings Formed on AISI D2 Steel

80%
Kılınc B., Demirkiran S., Sen U., Sen S.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
268-270
EN
In the present work, the corrosion behavior of Cr-Al-N coating formed on the pre-nitrided AISI D2 cold work tool steel by thermo-reactive diffusion technique in the powder mixture consisting of ferro-chromium, aluminum, ammonium chloride and alumina at 1000C for 2 h was investigated. The phases formed in the coating layers were Cr_2N, (Cr,Fe)_2N_{1-x}, AlN, and Fe_2N which were confirmed by X-ray diffraction analysis. The uncoated, nitrided, and Cr-Al-N coated specimens were placed in corrosive media (3.5 wt% salt solution). A standard saturated calomel electrode was used as a reference and graphite as a counter or auxiliary electrode. The effectiveness of the coatings in preventing corrosion was tested in the NaCl solution by electrochemical impedance studies using the Nyquist plots and potentiodynamic studies as well. Conclusively, the application of nitride and Cr-Al-N layers on AISI D2 steel increased its surface hardness and corrosion resistance. The corrosion resistance of Cr-Al-N coatings is higher than that of uncoated and nitrided steels.
3
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The Properties of Cr-Al-N Based Coatings Formed on AISI D2 Steel by Thermo-Reactive Diffusion Technique

80%
Kılınc B., Sen U., Sen S.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
271-273
EN
In this study, chromium aluminum nitride coating was applied on pre-nitrided AISI D2 steel by the thermo-reactive deposition technique in a powder mixture consisting of ferrochromium, aluminum, ammonium chloride, and alumina at 1000C for 2 h. Steels were gas nitrided for the purpose to enrich the surfaces with nitrogen of the steels in a nitrogen and ammonia atmosphere at 560C for 8 h. The effect of aluminum content in the powder mixture on the Cr-Al-N layer properties was investigated. The coated samples were characterized by X-ray diffraction analysis, scanning electron microscope, and micro-hardness tests. Chromium aluminum nitride layer formed on the pre-nitrided AISI D2 steel was compact and homogeneous. Electron dispersive spectrometer results showed that coating layer includes chromium, aluminum, and nitrogen. X-ray studies showed that the phases formed in the coating layers on the steel surfaces are Cr_2N, (Cr,Fe)_2N_{1-x}, AlN, and Fe_2N. The depth of the Cr-Al-N layer ranged from 10.01 ± 1.2 to 13.2 ± 1.7 μm, depending on the aluminum content. The hardness of the coated layers produced on AISI D2 steel are changing from 1743 ± 150 HV_{0.01} to 2067 ± 160 HV_{0.01} depending on bath compositions.
4
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Study of Silicon Nanocrystals Formation in Annealed Amorphous In Situ Nitrogen Doped Silicon Thin Films Obtained by Low Pressure Chemical Vapor Deposition

80%
Bouridah H., Haoues H., Beghoul M., Mansour F., Remmouche R., Temple-Boyer P.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
175-177
EN
In this work, we investigate the formation of silicon nanocrystals in annealed low pressure chemical vapor deposition in situ nitrogen doped silicon thin films (SiN_x) obtained at low temperature (465°C) by using a mixture of disilane (Si_2H_6) and ammonia (NH_3). Results show that nitrogen content in films plays an important role in defining the obtained films morphology in terms of crystallites sizes and their distribution. Indeed, according to the nitrogen content introduced in films, the crystalline state of films varies from a submicron crystalline structure to a nanocrystalline structure. An average silicon nanocrystalline size of 10 nm was obtained for film with x = 0.07 nitrogen content, annealed under a temperature of 850C during 2 h.
5
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Analytical Threshold Voltage Model Considering Quantum Size Effects for Nanocrystalline Silicon Thin Film Transistors

80%
Remmouche R., Fates R., Bouridah H.
Acta Physica Polonica A
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2017
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vol. 132
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issue 4
1230-1233
EN
This paper presents an analytical model calculating the threshold voltage in nanocrystalline silicon (nc-Si) thin film transistors by considering a granular morphology of silicon nanocrystallites forming the channel and using the two-dimensional the Poisson equation. The numerical calculations demonstrate that, according to the quantum size effects on both dielectric constant and band gap, the threshold voltage values are strongly related to the silicon crystallites structure. To justify the validity of our model suitable for implementation in circuit simulators such as SPICE, the simulation results obtained are compared with the available research data and they shows a satisfactory match, thus, demonstrating the validity of our model.
6
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Hybrid Organic/ZnO p-n Junctions, with n-Type ZnO, Grown by Atomic Layer Deposition

80%
Łuka G., Krajewski T., Szczerbakow A., Łusakowska E., Kopalko K., Guziewicz E., Wachnicki Ł., Szczepanik A., Godlewski M., Fidelus J.
Acta Physica Polonica A
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2008
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vol. 114
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issue 5
1229-1234
EN
We report on fabrication of hybrid inorganic-on-organic thin film structures with polycrystalline zinc oxide films grown by atomic layer deposition technique. ZnO films were deposited on two kinds of thin organic films, i.e. pentacene and poly(dimethylosiloxane) elastomer with a carbon nanotube content (PDMS:CNT). Surface morphology as well as electrical measurements of the films and devices were analyzed. The current density versus voltage (I-V) characteristics of ITO/pentacene/ZnO/Au structure show a low-voltage switching phenomenon typical of organic memory elements. The I-V studies of ITO/PDMS:CNT/ZnO/Au structure indicate some charging effects in the system under applied voltages.
7
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Influence of Thermal Oxidation Temperatures on the Structural and Morphological Properties of MoO_3 Thin Films

80%
Hojabri A., Hajakbari F., Emami Meibodi A., Moghri Moazzen M.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
307-308
EN
In this study, molybdenum (Mo) thin films have been deposited on Si substrate by dc magnetron sputtering. Then for preparation of MoO_3 thin films the thermal oxidation of Mo thin films under the oxygen flow was employed in the electrical furnace. The influence of the different thermal oxidation temperatures at 400, 600, 800 and 1000C on the structural and morphological properties of MoO_3 thin films were characterized by X-ray diffraction and atomic force microscopy, respectively. The results show that the crystallinity and surface morphology of the films are strongly dependent on the thermal oxidation temperatures.
8
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The Pressure Influence on the Properties of S-Phase Coatings Deposited by Reactive Magnetron Sputtering

80%
Fryska S., Baranowska J.
Acta Physica Polonica A
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2013
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vol. 123
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issue 5
854-857
EN
Reactive magnetron sputtering of austenitic stainless steel in nitrogen containing atmosphere was used to deposit coatings composed of S-phase. The process was conducted at constant temperature (200°C). The influence of total and partial nitrogen pressure on coating characteristics was investigated. It was observed that both total and nitrogen partial pressures have influence on coating composition and microstructure. Increasing nitrogen content in the S-phase coating can have a beneficial effect on its corrosion characteristics. It was also found that coatings deposited in the ambient of high nitrogen contents are composed of S-phase and the additional high-nitrogen phase, which is of crucial influence on mechanical properties of the coatings. It was also found that partial argon pressure can contribute to the changes in mechanical properties of the coatings.
9
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Effects of Thermal Annealing and Film Thickness on the Structural and Morphological Properties of Titanium Dioxide Films

80%
Çörekçí S., Kızılkaya K., Asar T., Öztürk M., Çakmak M., Özçelík S.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
247-248
EN
Titanium dioxide (TiO_2) thin films having different thicknesses of 220, 260, and 300 nm were deposited onto well-cleaned n-type silicon substrates by reactive DC magnetron sputtering and annealed in the range of 200-1000C in steps of 200°C. The effects of thermal annealing and thickness variation on the crystalline quality and surface morphology of the films were investigated by X-ray diffraction and atomic force microscopy measurements. It was found that the film quality and morphology depend on the annealing temperature. TiO_2 films exhibit a grain-like surface morphology. The root-mean-square roughness and grain size on the surface increase as a result of increasing film thickness.
10
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Influence of the Oxygen Plasma Treatment on Carbon Electrode and Capacity of Supercapacitors

80%
Kavaliauskas Z., Marcinauskas L., Valincius V.
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vol. 125
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issue 6
1316-1319
EN
Amorphous carbon electrodes were deposited using atmospheric pressure plasma torch from the mixture of argon and acetylene gases on the stainless steel substrates. The ratio of Ar/C_2H_2 was in the range of 15-55. The deposited coatings were immersed in low pressure oxygen plasma for 1 min. Scanning electron microscopy images show that when Ar/C_2H_2 ratio increases from 15 to 55, the electrodes surface roughness decreases. The Raman scattering spectroscopy results indicated that the I_{D}/I_{G} ratio decreases from 2.04 to 1.35. It was observed that with the increase of Ar/C_2H_2 ratio from 15 to 55, the capacity of supercapacitor increases from 16 mF to 36 mF. The electric capacity of capacitors has increased up to 7 times after their exposure in oxygen plasma.
11
Content available remote

Small-Angle X-Ray Scattering Studies of Pore Structure in Cellulose Membranes

80%
Ślusarczyk C., Fryczkowska B., Sieradzka M., Janicki J.
Acta Physica Polonica A
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2016
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vol. 129
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issue 2
229-232
EN
Small-angle X-ray scattering experiments were carried out on cellulose membranes obtained by phase inversion from a solution of the polymer in 1-ethyl-3-methylimidazolium acetate, by coagulation in water and selected primary alcohols. The invariant, Q, and the Guinier radius, R_{G}, computed directly from the small-angle X-ray scattering curve allowed us to estimate the pore dimensions and the pore volume fraction. It was found that both content and dimensions of pores depend on molecular mass of the coagulant used. Also, it was found that the dipole moment of coagulant molecules has a large influence on the volume content of the pores.
12
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Characterization of Fe-Nb-B Base Hardfacing of Steel

80%
Kilinc B., Cegil O., Abakay E., Sen U., Sen S.
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vol. 125
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issue 2
656-658
EN
Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions. In the present study, three different alloy compositions of the Fe-Nb-B were used for hardfacing of the AISI 1020 steel by tungsten inert gas welding process and analyzed. The coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the range of - 45 μm particle size with different ratio. The coatings' thickness was set to 2-3 mm on the substrate. Microstructure, phase analysis and hardness of the manufactured hardfacing alloys were characterized. Deposition results indicate good quality thick coating and porosity free of the hardfacings. X-ray diffraction analyses showed that the alloyed layers include iron borides, FeNbB and iron phases. It was shown that surface alloyed layer has composite structure including steel matrix and well distributed boride phases.
13
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Anodic Oxide Films on Niobium and Tantalum in Different Aqueous Electrolytes and Their Impedance Characteristics

80%
Verma N., Singh K., Marí B., Mollar M., Jindal J.
Acta Physica Polonica A
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2016
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vol. 129
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issue 3
297-303
EN
The anodic oxide films were prepared on the niobium and tantalum in aqueous electrolyte mixtures containing 1 M CH₃COOH + 1 M H₃PO₄ or 1 M CH₃COOH + 1 vol.% HF or 1 M CH₃COOH + 1 M H₃PO₄ + 1 vol.% HF at 30 V for 30 min. The barrier films were obtained on both niobium and tantalum surfaces in all electrolyte mixtures except niobium oxide film formed in 1 M CH₃COOH + 1 vol.% HF which is porous in nature. The anodic oxide films were characterized by FESEM. Also, electrochemical impedance spectroscopy at open-circuit potential on Nb and Ta was applied and obtained data were analyzed by fitting with four different equivalent circuits.
14
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Carbon Doped Austenitic Stainless Steel Coatings Obtained by Reactive Magnetron Sputtering

80%
Fryska S., Giza P., Jedrzejewski R., Baranowska J.
Acta Physica Polonica A
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2015
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vol. 128
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issue 5
879-882
EN
The paper presents the results of investigations of carbon doped austenitic stainless steel coatings (carbon S-phase) obtained by the reactive magnetron sputtering in the reactive atmosphere composed of argon and methane as a carbon source. Stainless steel targets were sputtered under different conditions. During the experiments the argon to methane proportion varied within a range 11/2-7/6. The other parameters such as temperature, pressure, sputtering power, etc. were kept constant. The phase composition was determined using the X-ray diffraction. Electron probe microanalysis (energy dispersive spectroscopy and wavelength dispersive spectroscopy) and glow discharge optical emission spectrometry techniques were used to study element composition of the coatings. Microstructure was investigated by scanning electron microscopy. It was found that varying the methane volume in the reactive atmosphere, it is possible to control the lattice parameter of the carbon S-phase.
15
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Enhanced Capacitance of Porous Carbon Electrodes through Deposition of Small Amounts of NiO

80%
Kavaliauskas Z., Marcinauskas L., Valatkevicius P.
Acta Physica Polonica A
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2011
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vol. 120
|
issue 1
66-69
EN
Amorphous carbon and NiO/carbon composites were used as an electrode material for supercapacitors. The investigations were performed to evaluate the influence of the Ar/C_2H_2 ratio on the capacitance values of carbon and NiO/carbon electrodes. The surface morphology of the carbon electrodes changes from snowflake-like to columnar with the increase of the Ar/C_2H_2 ratio. The Raman scattering spectroscopy results demonstrated that the I_{D}/I_{G} ratio decreases from 1.33 to 0.91 with the increase of the Ar/C_2H_2 ratio. It indicates the decrease of the sp^2 bonded carbon in the coatings. The specific capacitance of the carbon electrodes increases with the increase of the Ar/C_2H_2 ratio. The NiO/carbon electrodes show capacitance values 10 times larger as those of carbon electrodes. The largest specific capacitance of 27.7 F/g was obtained for NiO/carbon electrode, when carbon coating was deposited under Ar/C_2H_2=27.
16
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Formation and Characterization of Carbon and Nickel Oxide/Carbon Composites for Supercapacitors

80%
Kavaliauskas Z., Marcinauskas L., Valatkevicius P.
Acta Physica Polonica A
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2011
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vol. 119
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issue 2
253-255
EN
In this study a carbon and NiO/carbon electrodes were prepared and investigated. The surface roughness increases with the increase of the torch power. The addition of the NiO changes the surface structure from a snowflake-like to a mesh-like. It was demonstrated that the addition of the nickel oxide to amorphous carbon increases the specific capacitance of composite electrode. However, the NiO/carbon electrodes have a lower breakdown voltage values and longer charge-discharge cycles.
17
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Solution Growth of Well-Aligned ZnO Nanorods on Sapphire Substrate

80%
Jia G., Hao B., Lu X., Wang X., Li Y., Yao J.
Acta Physica Polonica A
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2013
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vol. 124
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issue 1
74-77
EN
Vertically well-aligned ZnO nanorods arrays were synthesized on sapphire substrates by chemical bath deposition. Those sapphire substrates were seeded to control the density and orientation of ZnO nanorods using sol-gel method. Well-aligned and uniformly distributed ZnO nanorods in a large scale were obtained with strongly (002) preferential orientation. The structural properties were characterized by X-ray diffraction spectrometer and morphological characteristics were analyzed by scanning electron microscopy, respectively. The ZnO nanorods are obvious hexangular wurtzite structure and preferentially oriented along the c-axis (002) and growth vertically to the substrates. The optical properties were further thoroughly studied. What is more, the influences of the strain between substrate and ZnO nanorods due to thickness of the ZnO seed-layer on the characteristics and optical properties of ZnO were also analyzed.
18
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Characterization of Nitride Thin Films Using SEM and EDX

71%
Mammeri F., Chekour L., Rouag N.
Acta Physica Polonica A
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2013
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vol. 123
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issue 2
294-295
EN
The chromium nitride thin films have became more and more popular in the last years because of their very good physical, chemical and mechanical properties. The present study relates to thermal stability of hard thin films of chromium nitride CrN, carried out physical vapour deposition. We studied the influence of the annealing temperature on the morphology of CrN films, deposited on silicon substrate using magnetron sputtering. The characterizations are examined using scanning electron microscope equipped with energy dispersive X-ray spectroscopy. Annealing treatments in N_2 at 600-1000C for 1 h are performed on CrN coating samples for 530 nm thickness. At low temperature, the results show a thermal stability of these coatings. The Cr_2O_3 phase is completely replaced by the CrN phase at temperature above 1000°C. The results given by scanning electron microscopy-energy dispersive X-ray spectroscopy and X-ray diffraction are compared.
19
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Growth Rate and Sensing Properties οf Plasma Deposited Silicon Organic Thin Films from Hexamethyldisilazane Compound

71%
Saloum S., Alkhaled B.
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issue 3
484-489
EN
Silicon organic thin films have been prepared by RF hollow cathode plasma chemical vapor deposition system, from hexamethyldisilazane (HMDSN) as the source compound, under different plasma conditions, namely feed gas and applied RF power. The feed gas has been changed from argon to nitrogen, and the power has been varied between 100 W and 300 W in N_{2}/HMDSN plasma. The plasma active species (electrons, ion flux rate, and UV radiation) contributing to the films growth mechanisms have been identified by electrical probes and optical emission spectroscopic analysis. The films have been investigated for their thickness and deposition rate, using quartz crystal microbalance, and sensing properties relating to humidity and gas (NH_{3}, CO_{2} and O_{2}) sorptive investigations, using the piezoelectric effect of quartz crystals of the quartz crystal microbalance. The effect of the different plasma conditions on the plasma phase characteristics and deposited thin films properties, as well as the correlations between deposition rate and plasma characteristics and between sorptive properties, water contact angles and thin films surface morphology are reported.
20
Content available remote

Structural Characteristics and Optical Properties of Thermally Oxidized Zinc Films

71%
Rusu D., Rusu G., Luca D.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6
850-856
EN
Zinc oxide (ZnO) thin films (with thickness ranged from 780 nm to 1150 nm) were prepared by thermal oxidation in air (at 600-700 K, for 20-30 min) of vacuum evaporated metallic zinc films. The Zn films were deposited on glass substrates at room temperature. The crystalline structure of ZnO thin film samples was investigated using X-ray diffraction technique. The diffraction patterns revealed that the ZnO thin films were polycrystalline and have a wurtzite (hexagonal) structure. The film crystallites are preferentially oriented with (002) planes parallel to substrate surface. Some important structural parameters (lattice parameters of the hexagonal cell, crystallite size, Zn-O bond length, residual stress, etc.) of the films were determined. The surface morphology of the prepared ZnO thin films, investigated by atomic force microscopy, revealed a uniform columnar structure. The spectral dependence of transmission coefficient has been studied in the wavelength range from 300 nm to 1700 nm. The optical energy band gap calculated from the absorption spectra (supposing allowed direct band-to-band transitions) are in the range 3.17-3.19 eV. The dependence of the microstructural and optical characteristics on the preparation conditions (oxidation temperature, oxidation time, etc.) of the oxidized zinc films is discussed.
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