Thin Solid Films

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Current Flow in Thin Solid Films: Thermionic Emission and Tunneling

Current Flow in Thin Solid Films: Thermionic Emission and Tunneling

CURRENT FLOW IN THIN SOLID FILMS THERMIONIC EMISSION AND TUNNELING Thesis by Stephen L Kurtin In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy (Submitted September 18,[.]

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Raman structural studies of phthalocyanine thin solid films.

Raman structural studies of phthalocyanine thin solid films.

Vanadyl phthalocyanine has been studied as a high density optical storage material"^. The VOPc films were prepared by vacuum vapor deposition onto polymethylmethacrylate substrates and then annealed. A laser of wavelength in the region of 800nm evaporates the organic material and forms a pit (writing). The optical defects are detected or "read" a later time. Double and triple layer structures containing VOPc have also been tested.

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ABSTRACTS: April 197868-73

ABSTRACTS: April 197868-73

The Effect of Silver Interdiffusion on the Catalytic Activity of Thin Platinum and Palladium Films in the Reduction of Ag,S Films.. ABERMANN, Thin solid Films,.[r]

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Surface morphology and optical properties of copper nitride thin film synthesized by DC sputtering

Surface morphology and optical properties of copper nitride thin film synthesized by DC sputtering

An application of thin film technology has revolutionized the field of optics and electronics. The need for new and improved optical and electrical devices has stimulated the study of thin solid films of elements, as well as binary and ternary systems, which controlled composition and specific properties, and has consequently accelerated efforts to develop different thin film deposition techniques. Among advantages of thin films devices are low power consumption, relatively small and reduction occupied space and higher speed performance (Sakrani, 2004).
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Volume 8 | Issue 4 - 2018

Volume 8 | Issue 4 - 2018

The CdSe nanocrystalline thin films were fabricated on different substrates (silicon, indium tin oxide and glass) with different thicknesses (225, 250, and 300) nm by the pulsed laser deposition (PLD) technique. These thin films were characterized by the structural and optical measurements. From the X-ray diffraction (XRD), it was found that the thin films had hexagonal wurtzite structure. Crystallite size of the thin films increased from 13.56 nm to 21.368 nm with the increased thickness from 225nm to 300 nm. The atomic force microscopy images showed that the surface topography of the thin films got more homogeneity with the increased thickness. Optical properties have been performed by investigating the transmittance spectra in the spectral region (300–700) nm, and it was found that the thin films had the transmittance which increased with the increased wavelengths in the visible region, and the edge energy gap shifted from 1.8 eV to1.7 eV with the increased thickness from 225 nm to 300 nm, making the thin films suitable to be used in the optoelectronic and solar cell applications. The resistance of thin films was changed with the relative humidity, and their sensitivity was increased with the increased grain size and thickness, making CdSe thin films suitable to be used as a humidity sensor. Keywords : CdSe; Nanocrystalline; Humidity Sensor.
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Quartz Crystal Microbalance Studies of Magnetic Mechanisms of Atomic-scale Friction.

Quartz Crystal Microbalance Studies of Magnetic Mechanisms of Atomic-scale Friction.

The rise of oil companies Socony, Exxon, Socal, Texaco, British Petroleum and others in the late 1800s and early 1900s marked a change in usage from vegetable and animal oils and fats to mineral oils as lubricants. This prompted research around the world in thin film lubrication. Gustav-Adolphe Hirn in the 1840s developed a friction balance for studies of friction of bronze bearings dipped in lubricant. He found a first order velocity dependence for lubricated coefficient of friction at constant temperature and demonstrated the usefulness of mineral oil as a lubricant. Robert Henry Thurston in 1879 was the first to report that coefficient of friction undergoes a minimum upon transition from increased loading and increased speed from fluid film to boundary lubrication. Richard Stribeck systematized journal friction experiments in the 1890s, revealing a curve consistent with the minimum recognized by Thurston.
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Tunable, Source-Controlled Formation of Platinum Silicides and Nanogaps from Thin Precursor Films

Tunable, Source-Controlled Formation of Platinum Silicides and Nanogaps from Thin Precursor Films

for NEM switch applications. The Pt-rich silicide films possess a modest increase in contact resistance compared to as-deposited Pt, and exhibit a 50% increase in modulus and hardness. We propose that these films may be ideal materials for NEM contact switches and may ultimately enable the commercialization of these devices. Additionally, we predict that our method of adjusting the silicide stoichiometry and properties by changing the precursor layer thickness ratios will be also applicable to other metal silicides (e.g., titanium, nickel, tungsten, cobalt, molybdenum, and chromium silicide).
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Developing Non-Invasive Processing Methodology And Understanding the Properties Of Spin Coated Organic Semiconductors for Organic Thin Film Transistors with Polymeric Gate Dielectric

Developing Non-Invasive Processing Methodology And Understanding the Properties Of Spin Coated Organic Semiconductors for Organic Thin Film Transistors with Polymeric Gate Dielectric

The chemical structure of CuPc is shown in Fig. 1(a). The material used was commercially available from Aldrich chemical (98% purity) and no further purification process was performed. CuPc thin films were spin coated. Both bare and PMMA spin-coated glass substrates (Corning 7059) were used to study the optical and structural properties of the CuPc films. PMMA was spun at 4000 rpm for 40s and then cured for 30 min at 100 °C to form a uniform coating about 680 nm thick. PMMA has a high resistivity (>2 · 10 15 Ω cm) and its dielectric constant is similar to that of silicon dioxide (e =2.6 at 1 MHz, e = 3.9 at 60 Hz). In addition, CuPc OTFTs were fabricated using PMMA as gate dielectric. An inverted staggered configuration was used, as can be seen in Fig. 1(b). The bottom gate was a chromium layer thermally evaporated on crystalline silicon. To define and isolate the devices, CuPc was evaporated through a shadow mask. Finally, gold was also evaporated through a shadow mask to form the drain and source electrodes. The CuPc and gold thicknesses were 200 and 60 nm, respectively. The OTFTs had a channel length (L) and width (W) of 120 and 600 µm, respectively. The maximum process temperature was 100 °C, corresponding to the PMMA baking.
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Effect of Annealing Temperature and Atmosphere to Surface Solid Phase Reaction of Sapphire Substrates and Spin Coated Copper Nitrate Gel Films

Effect of Annealing Temperature and Atmosphere to Surface Solid Phase Reaction of Sapphire Substrates and Spin Coated Copper Nitrate Gel Films

Cu O Al O + → 2CuAlO (1) However, the solid phase reaction in the present work is accompanied by dif- fusion of oxygen and copper into sapphire substrate. In the annealing under ni- trogen flow, it is considered that the supply of oxygen to the reaction interface is not sufficient and the formation of CuAlO 2 stops at a specific depth. As a result,

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Development of superlattice CrNNbN coatings for joint replacements deposited by High Power Impulse Magnetron Sputtering

Development of superlattice CrNNbN coatings for joint replacements deposited by High Power Impulse Magnetron Sputtering

The effect of the deposition method on bulk coating density was analysed by cross sectional SEM and FIB SEM analyses, Figure 2. Figure 2a is a FIB SEM image of a coating deposited by arc evaporation. A volume of the coating has been captured where a large droplet, (~ 2 µm in diameter) produced at the arc spot on the evaporation cathode has been deployed on the substrate surface at the initial stages of the coating growth. Once on the substrate, the droplet solidifies forming a pore in the centre of the feature due to the volume reduction occurring during the liquid-solid transformation. As the deposition process progresses, the coating overgrows the macro particle, (solidified droplet) which results in formation of a large dome shaped growth defect protruding a few microns above the coating surface. The growth defect engulfing the macro particle is separated from the surrounding coating by a void, which develops due to the atomic shadowing effect, but probably also due to the difference in the growth rates between the growth defect and the surrounding defect free area.
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Exciton dynamics in solid state green fluorescent protein

Exciton dynamics in solid state green fluorescent protein

In order to gain insight into the dynamic processes of Frenkel excitons in solid-state eGFP, we have subse- quently recorded the time-resolved fluorescence of the three main recombination bands present in Fig.2(a). They can be seen in Fig.2(b). While all fluorescence bands decay on a ns-scale, the individual decay curves look different. The transitions at 508 nm and 540 nm decay mono-exponentially in good approximation (the 540-nm-band shows a slower turn-on-time due to the involvement of phonons), their decay times can be de- termined to be almost equal (τ(508 nm) = τ(540 nm) = 2.45 ns). Note that those exciton lifetimes are notably shorter compared to similar investigations on eGFP in solution, where decay times of 3.1-3.4 ns are observed 12 .
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Novel Metal Silicide Thin Films by Design via Controlled Solid-State Diffusion

Novel Metal Silicide Thin Films by Design via Controlled Solid-State Diffusion

The heating holder is equipped with a thermocouple sensi- tive to ± 1 ¡C. All source-limited solid-state diffusion sam- ples (Figure 1 and Figure 2) were subject to a similar an- nealing treatment which included the heating up to 500 ¡C (heating rate: 30 ¡C/min) and holding at 500 ¡C for 10 min. This was followed by heating up to 600 ¡C (heating rate: 30 ¡C/min), holding at 600 ¡C for 10 min and rapid cooling to 50 ¡C (cooling rate: 85 ¡C/min). The kinetically-limited solid-state diffusion sample was heated up with a heating rate of 30 ¡C/min until 200 ¡C and rapidly quenched to conserve the Pt 3 Si phase. Subsequently, the sample was
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Fabricating and Characterizing Chalcogenide Thin Films as Light Absorbing Layers in Solar Cells

Fabricating and Characterizing Chalcogenide Thin Films as Light Absorbing Layers in Solar Cells

problems associated with the use of gallium and selenium in a similar fashion as CZTS. Much academic and industrial interest has been paid to CIS thin films due to its particular optoelectronic properties. 4, 33-34 This is more apparent in the field of PVs in which the ternary semiconductor CIS is often sought for its near optimum band gap (1.54 eV) and high theoretical efficiency (28.5 %). 35-36 The chalcopyrite crystal structure (Figure 1.6) of CIS has been shown to have influence into the effectiveness of CIS as an absorber layer as well. 36-38 The multitude of methods for obtaining and depositing CIS has also been intensely studied: radio frequency sputtering, thermal evaporation and chemical vapour deposition are just a few of the methods that can be utilized for effective absorbing layers. 39-43 However, the scalability of many of these techniques is quite limited. Much research has been done to increase the efficiency of these thin film solar cells while decreasing the cost of synthesis and production. 44 CIS shows great potential to replace CIGS solar cells with laboratory efficiency up to 11.6 %. 45-46 Drawbacks of
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InxSn1-xO2 Thin Films Synthesized via Spray Pyrolysis Method and Characterized for Glucose Detection by Means of Impedimetric Sensors

InxSn1-xO2 Thin Films Synthesized via Spray Pyrolysis Method and Characterized for Glucose Detection by Means of Impedimetric Sensors

temperature range from 400 °C to 450°C, which is known to be the optimal range for the formation of SnO2 films. The conditions of sprayer were: 3 atm. in pressure carrier gas, and 30 cm in substrate-to-nozzle distance. The sprayed metallic salt solution on to a hot substrate, chemical reaction takes place on the heated substrate caused to pyrolitically decomposes and a thin layer of SnO2 is form, the setup of the of the deposition equipment is illustrated in the Figure (1):

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Impact of nanostructured thin ZnO film in ultraviolet protection

Impact of nanostructured thin ZnO film in ultraviolet protection

In this study, thin ZnO films were prepared using a sol-gel method on glass substrates, and the structural and optical properties of these films were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-visible spectrophotometry. For the ZnO-nanoparticle preparation, the precursor used was zinc acetate dihydrate (ZnAc; Zn[C 2 H 3 O 2 ] 2 ⋅ 2H 2 O, 99.5%; Merck Millipore, Billerica, MA, USA), and indium(III) chloride, aluminum acetate, and lithium acetate were used as doping sources. Pure ethanol and triethanolamine (TEA) were used as solvent and stabilizer, respectively. Indium(III) chloride, aluminum acetate, and lith- ium acetate were purchased from Sigma-Aldrich (St Louis, MO, USA). Reagent-grade ethanol with 99.9% purity was used. The triethanolamine:ZnAc molar ratio was maintained at 2:5. Additional details of the preparation process have been reported elsewhere. 32,33 The nanostructured thin ZnO films
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Hydrophobic silica thin films by sol-gel processing and spin coating technique at low temperature

Hydrophobic silica thin films by sol-gel processing and spin coating technique at low temperature

Although water contact angle of hydrophobic silica thin film is quite high, but the roll off angle is quite high as water droplet is not easily rolls and the droplet trend to stick to the surface. This is because large hysteresis is existed in this state. This hydrophobic equilibrium state is the Wenzel state [20] which water penetrates into the rough surface cavities. This can be reduced by increasing time or temperature during heat treatment of silica films formation. Another state is Cassie equilibrium state [20] where water droplet sits on the asperities of the surface while the air is entrapped in the structure below them. This state makes the droplet easily roll off.
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Study of Structural, Optical & Solid State Properties of Nanocrystalline Cadmium Sulfide Thin Films

Study of Structural, Optical & Solid State Properties of Nanocrystalline Cadmium Sulfide Thin Films

Fig. 2 shows the optical absorbance spectra of cds thin films for all four cadmium sources. All the films shows low absorbance in the visible/near infrared region from ~500nm to 1100nm. However the absorbance is more than 80% in the ultraviolet region. It is observed that with the cadmium source the absorbance edge shifts towards the longer wavelengths. Similar behaviors in the optical spectra of cds films prepared by other technique have been reported elsewhere [5,6]. The sharp fall in absorbance near 500nm is an identification of good crystallinity of films. [8,9]
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Synthesis and Properties of Barium Titanate Solid Solution Thin Films on Copper Substrates

Synthesis and Properties of Barium Titanate Solid Solution Thin Films on Copper Substrates

Film consolidation may have occurred during or immediately after deposition resulting in a chemical gel. In other cases, the films must be exposed to higher temperatures (or allowed to sit in ambient conditions for some time to allow organic evaporation) to drive out remaining organics and to consolidate the gel. The thermal processes that are used to consolidate gels can be described by two categories. Thermolysis is a general term describing the removal of organics by heat. It can include either combustion or heating in a reducing atmosphere to drive organics through heat and partial pressures alone. Pyrolysis is a form of thermolysis that is specific to heat treatment in oxidizing atmospheres, such as air. Here organics are reacted with oxygen in the air to break bonds and form species that are easier to extract. Pyrolysis is by far the most utilized term in the literature, however many processes may actually be better described by thermolysis. The most common thermolysis treatment of thin films is a hot-plate ‘dry.’ Here the film is taken directly from the spin coater and placed onto the surface of a hot-plate with a temperature ranging between 200 and 400°C. During this step, the films experience significant shrinkage -- as much as 30% of the original thickness. The relatively high temperatures of the hot-plate thermolysis are necessary to remove a large fraction of the organic constituents prior to a collapse of the amorphous structure upon later heat treatments that would trap remaining organics. 171
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Novel nanostructured biomaterials: implications for coronary stent thrombosis

Novel nanostructured biomaterials: implications for coronary stent thrombosis

Results: The nanotopographic features of material surface, stoichiometry, and wetting proper- ties were found to be significant factors in dictating platelet behavior and cell viability. The TiBN films with higher nitrogen contents were less thrombogenic compared with the biased carbon films and control. The carbon hybridization in carbon films and hydrophilicity, which were strongly dependent on the deposition process and its parameters, affected the thrombo- genicity potential. The hydrophobic CNT materials with high nanoroughness exhibited less hemocompatibility in comparison with the other classes of materials. All the thin film groups exhibited good cytocompatibility, with the surface roughness and surface free energy influenc- ing the viability of cells.
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Nickel-Doped TiO2 Multilayer Thin Film for Enhancement of Photocatalytic Activity

Nickel-Doped TiO2 Multilayer Thin Film for Enhancement of Photocatalytic Activity

Fig. 11 shows methylene blue degradation rate as a function of light irradiation time (6 hours). Methylene blue degradation rate was obtained from the ratio of the absorbance at the maximum absorption wavelength (664nm) in Fig. 10. In the same light irradiation period, the P25 + Ni-SP four-layer thin film showed the highest methylene blue degradation rate of 76.1%. Meanwhile, P25 single-layer thin film showed the lowest methylene blue degradation rate of 57.7%. In addition, methylene blue degradation rate of the P25 four-layer thin film was 69.1%, which was similar to 68.7% of the P25 + Ni-SP single-layer thin film. This was attributed
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