Top PDF Tetrathiotetracene thin film morphology and electrical properties

Tetrathiotetracene thin film morphology and electrical properties

Tetrathiotetracene thin film morphology and electrical properties

Abstract. The electrical properties of organic thin films are determined by their chemical constituents and the morphology of the films deposited. In this paper the morphology of vacuum sublimed (7∙10 -6 mbar) tetrathiotetracene (TTT) thin films is shown to be strongly affected by the thermal deposition temperature (222-350 K) and rate of deposition. Mostly needle-like morphologies are identified by scanning electron microscopy. Optimal TTT purity (a pre-requisite for device preparation via subsequent oxidation) is evidenced by their initially low electrical conductivity. Altering the TTT morphology, by variation of the evaporation parameters, strongly affects this base electrical conductivity. Four probe conductivity measurements and charge extraction by linear increasing voltage methods are used to characterize film electrical properties. In-plane conductivity of up to 7.03∙10 -5 S/cm is achieved for pure TTT thin films. Subsequent aerial oxidation resulted in a 3.4-fold increase in electrical conductivity.
Show more

12 Read more

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

Any solid or liquid object with one of its dimensions very much less than that of the other two may be called a “thin film” (George, 1996). The most commonly observed phenomenon associated with thin films, which attracted the attention of physicists as early as the second half of seventeenth century, is the fascinating colours on a thin film of oil coating on the surface of water.

25 Read more

Study Of Electrical And Optical Properties Of Thin Films

Study Of Electrical And Optical Properties Of Thin Films

There are different film statement methods, however one which is advantageous and of minimal effort is compound vapor affidavit (CVD). In the CVD technique SnCI 41, SnC122 or organometallic mixes of tin, for example, tetramethyl tin 3 or dibutyl tin diacetate 4, have been utilized as tin hotspots for the statement of SnO2 films. The vapors of an appropriate tin-bearing compound are conveyed into the reactor and disregarded the warmed substrate together with an oxidizing specialist. In the reactor,

14 Read more

Electrical properties of copper nitride thin film prepared by reactive DC sputtering

Electrical properties of copper nitride thin film prepared by reactive DC sputtering

Wang et al. (1998) prepared copper nitride films by changing the content of nitrogen gas at various sputtering pressures. They concluded that the band gap of the film could be engineered by controlling the nitrogen gas pressure. A calculation of electronic structure showed that copper nitride is a semiconductor with a small indirect band gap. It was also predicted that the copper nitride is a better conductor when it is rich in copper and that extra copper produces an increase in the lattice constant. (Monero-Armenta et al., 2004)
Show more

28 Read more

Characterization of Phosphoric Acid Doped N-type Silicon Thin Films Printed on ITO Coated PET Substrate

Characterization of Phosphoric Acid Doped N-type Silicon Thin Films Printed on ITO Coated PET Substrate

In this paper n-type polycrystalline silicon thin films deposited on ITO coated polyethylene terephthalate (PET) substrate by screen printing technique have been studied. The phosphoric acid with different concentration used as doping source to create n-type silicon powder which is dissolved in solvent to obtain n- type silicon pastes have three different doping concentration and constant viscosity . These pastes used to print n-type polycrystalline silicon thin films with thicknesses of 611 8 nm for etch and different phosphorus doping concentrations. Among the techniques applied to analyze the properties of poly-Si thin layers to evaluate the effect doping variation. X-ray diffraction (XRD) technique was used for the determination of the crystallites size (D) and the stress in poly-Si thin films. The surface morphology and roughness carried out by Scanning electron microscopy (SEM) and atomic force microscopy (AFM). Thin film components elements detected by (EDX) attached with SEM system. The electrical properties such as resistivity, carrier concentration and Hall mobility were carried out by Hall Effect measurements. Optical transmittance and the transmittance ratio and others optical properties of the films are reported. Details on the sample preparations and experimental details will be presented.
Show more

13 Read more

Electrical Properties of Nano TiO2 Thin Film Using Spin Coating Method

Electrical Properties of Nano TiO2 Thin Film Using Spin Coating Method

ameter after calcination at 400˚C, in pure anatase phase, anatase (53.4%) and rutile (46.6%) phase after calcina- tions at 600˚C and the particle sizes were 22.6 nm and 29.3 nm respectively, and 46.2 nm in diameter after cal- cinations at 800˚C, in pure rutile phase [10]. Therefore, this work seeks to investigate the electrical properties of the synthesized nano-TiO 2 for opto-electronics application.

6 Read more

Optical and electrical properties of Mg/Co bilayer thin film metal hydrides

Optical and electrical properties of Mg/Co bilayer thin film metal hydrides

of bilayer thin films have been performed for 1 hour at different temperature. Hydrogenation of pristine and annealed bilayer structure has been performed at different hydrogen pressure for half an hour. The optical transmission increased with hydrogen pressure and also the band gap of thin films found to be increase with hydrogen pressure. Pristine Mg/Co bilayers show ohmic behavior and conductivity increase with hydrogen pressure. After annealing bilayers show semiconductor nature and conductivity has been found to be increased with annealing temperature and decreased with hydrogenation. Raman spectra of these sample shows decreasing intensity of peaks with annealing and hydrogenation. The relative resistivity varies nonlinearly with time and increases with hydrogen pressure. Surface morphology of annealed and annealed hydrogenated bilayer structure has been confirmed by optical microscopy.
Show more

6 Read more

Characteristics of Electron Beam Evaporated and Electrodeposited Cu2O thin films – Comparative study

Characteristics of Electron Beam Evaporated and Electrodeposited Cu2O thin films – Comparative study

solar energy conversion, photocatalysis, sensors etc. has been prepared in thin film form using an electrochemical (electrodeposition) and a physical method (electron beam evaporation). A systematic study on the properties of cuprous oxide thin films deposited by electrochemical and physical method revealed the suitability of cuprous oxide thin films in two different applications. The electrodeposited cuprous oxide thin films had microcrystalline structure with a preferred orientation along (111) direction. The film was densely packed with cone- like microstructures. They have also exhibited good electrical conductivity and low optical band gap. In contrast, electron beam evaporated films were nanocrystalline in nature. These films had a highly porous net-like structure. The films are highly resistive when compared to electrodeposited films and also exhibited a larger band gap. These results reveal that he electrodeposited and electron beam evaporated cuprous oxide thin films are suitable for the preparation of photovoltaic cells and gas sensors respectively.
Show more

11 Read more

Influence of TiO2 thin film annealing temperature on electrical properties synthesized by CVD technique

Influence of TiO2 thin film annealing temperature on electrical properties synthesized by CVD technique

be used such as chemical vapor deposition (CVD), sol-gel deposition, spin coating and spray pyrolysis (M. Alzamani et al., 2013). However, CVD technique consider as a promising method for the preparation of high quality thin films over a large surface area with well controlled composition and low defect density (SangChul Jung et al., 2013).

5 Read more

Optical and Electrical Properties of TiO2 Doped Fe2O3 Thin Film Prepared by Spray Paralysis Technique

Optical and Electrical Properties of TiO2 Doped Fe2O3 Thin Film Prepared by Spray Paralysis Technique

is the most stable iron oxide compound material and is widely used in photoelectrodes, gas sensing, catalysts, magnetic recording, and medical fields. Iron oxide films can be used in a wide range of applications. Properties, such as high refractive index wide band gap and chemical stability make them suitable for use as gas-sensors. These

7 Read more

Synthesis and Characterization of Cdxni1-Xse Thin Film and their Optical Properties

Synthesis and Characterization of Cdxni1-Xse Thin Film and their Optical Properties

Cd x Ni 1-x Se thin films are developed by electrochemically deposition technique on stainless steel substrates in galvanostatics mode from an aqueous acidic bath. Which contain CdSO 4 , NiNO 3 and SeO 2 .the properties of film are studies by deposition parameters such as deposition time, current density, deposing potential, pH of bath, are optimized and crystal structure are studied by X-Ray diffraction analysis. Optical properties studied with polysulphide solution by measuring Isc and Voc and surface morphology observed by scanning electron microscopy shows the deposited film are well adherent and uniform.
Show more

5 Read more

Electrical properties of thin metallic films

Electrical properties of thin metallic films

The Hall coefficient and conductivity of silver films were measured by a DC method and comparisons with the theoretical calculations of Fuchs and Sondheimer were made. Films from 150 A. to 1500 A. in thickness were deposited by evaporation at pressures below 10^-2 microns. The electrical properties were studied at liquid nitrogen, dry ice and acetone, and room temperatures. Film thickness measurements were made by the interferometer method. Electron diffraction and electron micrograph pictures were taken to study agregation and to check on the purity of the films. The electron micrographs show aggregation in films less than 300 A. thick. The electrical measurements also indicate this change in the thinnest films. A variation of Hall coefficient and conductivity with thickness was found but only qualitative agreement between theory and experiment was indicated.
Show more

16 Read more

Morphology and electrical properties of polyethylene blends

Morphology and electrical properties of polyethylene blends

Although it is appreciated that structural factors can influence such dielectric failure processes in polymeric materials (48), few attempts have been made to study this area in detail, particularly in relating microstructure and other material properties to electrical breakdown phenomena. Most investigations have adopted crude approaches to the topic of morphology (56-62). Despite this reservation, a number of papers published in the late 70s and early 80s are of particular interest within the context of the work described subsequently. In these, a correlation between spherulitic development and dielectric strength was reported (58-62) and it was argued that the regions between spherulites dominate the breakdown behaviour. Hence, spherulitic development led to reduced electrical strength. Although a number of possible explanations were proposed to account for this behaviour (62), the true reason is still unclear. Wagner (63) showed that the discharge channels in thin polypropylene films were confined to spherulitic boundaries. Leda (64) showed that contradictory to the above data, that the inception voltage of electrical trees increased with spherulitic radius and that the tree channels go round the spherulites, a claim that was substantiated by direct observation of tree channels (65). Fava (66) and Fischer (67) showed that the dielectric strength increases with increasing molar mass, it was suggested that regions containing low molecular mass material facilitated local breakdown events and partial discharges, possibly due to local voiding intrinsic to these regions.
Show more

220 Read more

Improvement of optical transmittance and electrical properties for the Si quantum dot embedded ZnO thin film

Improvement of optical transmittance and electrical properties for the Si quantum dot embedded ZnO thin film

crystalline quality of Si QDs embedded in the ZnO matrix. Since the crystalline properties of the ZnO matrix can influence its optical and electrical properties [15], the XRD patterns of the Si QD-embedded ZnO thin films annealed at different temperatures are examined and shown in Figure 2a, fine-scanned from 30° to 40°. A main diffraction signal is observed at approximately 34.5° for all the samples. As shown in Figure 2b and its inset, this sig- nal can be decomposed into two components in Gaussian form with peaks located at about 34.3° and about 36.3°, which are contributed from (002) and (101) orientations of ZnO [16]. In Figure 2a, the crystallization intensity of the ZnO matrix is slightly reduced when increasing T ann .
Show more

6 Read more

Optical and Electrical Properties of Neodymium Doped Cadmium Selenide Nanocrystalline Thin Film

Optical and Electrical Properties of Neodymium Doped Cadmium Selenide Nanocrystalline Thin Film

The pure and CdSe:Nd nanocrystalline thin films were prepared by chemical bath deposition method. X-ray diffraction pattern of pureand CdSe:Nd nanocrystalline thin films clearly show the film is sphalerite cubic (zinc blende type) structure. Photoluminescence spectra of pure and CdSe:Nd nanocrystalline thin films were recorded and the strongest PL intensity is found at 601 nm. This might have happened because of another energy level formed between the valence band and conduction band of pure CdSe. The prepared films are having sufficient potential to be used for solar cell applications.
Show more

6 Read more

Influence of tio2 thin film annealing temperature on 
		electrical properties synthesized by CVD technique

Influence of tio2 thin film annealing temperature on electrical properties synthesized by CVD technique

The results obtained probably caused by condition of thin film produced during the process of deposition is too thin. The formation of a crack affects the cluster size and indirectly reduce the movement of electrons due to the low quality of TiO 2 thin film.

6 Read more

Optical and Electrical Properties of Cu-Based Thin Films by Aerosol Assisted Chemical Vapor Deposition

Optical and Electrical Properties of Cu-Based Thin Films by Aerosol Assisted Chemical Vapor Deposition

Cu-based thin films with doping of Zn and Al were synthesized by aerosol-assisted chemical vapor deposition (AACVD). The AACVD allows simple fabrication method which produced homogenous film when deposited on glass substrates. The structural, optical transmittance and electrical properties of Cu-based thin film with Zn and Al doping were obtained by X-ray diffraction (XRD), UV-Vis spectroscopy and 4-point probe, respectively. XRD results showed peaks for ZnO and CuAlO 2 indicating that binary Cu thin film with Zn and Al doping was
Show more

7 Read more

Electrical Properties of the Al/CuInSe2 Thin Film Schottky Junction

Electrical Properties of the Al/CuInSe2 Thin Film Schottky Junction

on the electrical carrier transport through the junctions [29] [30]. As proved experimentally, most of these junc- tions have an electrical behavior close to the theoretical ideal thermionic emission current model usually used [31]-[36], although the study of the temperature dependence on the current-voltage (IV) and the capacitance- voltage (CV) characteristics of these junctions gives more detailed information about their conduction processes and the nature of the potential barrier [37]-[43].

13 Read more

Effect of Dip Time on Electrodeposited Zinc Oxide Nanofilm

Effect of Dip Time on Electrodeposited Zinc Oxide Nanofilm

Cathodic electrodeposition technique has been recognized as the effective method for the production of metal oxide thin films, particularly ZnO thin films due to its simplicity, low temperature process, high deposition rate, low cost technique and suitability for large area substrate. This technique used a very low cathode voltage or current to produce the ZnO thin film on any conductive substrate such as a transparent conducting oxide [5] or any other metal plate [17]. In this deposition technique, the film thickness, electrical structural, morphology and optical properties can be controlled by the various deposition parameters such as: current density, applied potential, deposition time and the concentration of the electrolytic bath. In this work, ZnO thin films were electrodeposited at room temperature at varying deposition time.
Show more

5 Read more

Effects of the electrical conductivity and orientation of silicon substrate on the synthesis of multi walled carbon nanotubes by thermal chemical vapor deposition

Effects of the electrical conductivity and orientation of silicon substrate on the synthesis of multi walled carbon nanotubes by thermal chemical vapor deposition

A large number of experimental parameters for multi- walled carbon nanotubes (MWNTs) grown by chemical vapor deposition (CVD) have been investigated includ- ing the type of thickness of catalytic metal films [1,2], the substrate temperature [3,4], the ammonia gas flow rates [5,6], and supporting substrate, etc. [7,8]. Among those parameters, the control of the catalyst particles is one of the most important factors that determine the structure and morphology of MWNT properties such as lengths, diameters, and density [9-11]. However, a basic growth mechanism explaining the way metallic atoms interact with carbon to nucleate, grow, and heal carbon nanotubes (CNTs) still needs to be understood. Previ- ously, we investigated the effect of the electrical con- ductivity of the Si(100) substrate on the control of the growth of MWNTs and found that as the electrical con- ductivity of the silicon substrate increased, the average
Show more

6 Read more

Show all 10000 documents...

Related subjects