排序方式: 共有55条查询结果,搜索用时 0 毫秒
11.
Amorphous silicon thin films were formed by chemical vapor deposition of reactive particle beam assisted inductively coupled plasma type with various reflector bias voltages. During the deposition, the substrate was heated at 150 °C. The effects of reflector bias voltage on the physical and chemical properties of the films were systematically studied. X-ray diffraction and Raman spectroscopy results showed that the deposited films were amorphous and the films under higher reflector voltage had higher internal energy to be easily crystallized. The chemical state of amorphous silicon films was revealed as metallic bonding of Si atoms by using X-ray photoelectron spectroscopy. An increase in reflector voltage induced an increase of surface morphology of films and optical bandgap and a decrease of photoconductivity. 相似文献
12.
Phadtare Varsha D. Parale Vinayak G. Puri Vijaya R. Park Hyung-Ho 《Journal of Electroceramics》2019,43(1-4):64-72
Journal of Electroceramics - The microwave dielectric properties of the multiwalled carbon nanotubes (MWCNT) thick film, Ca1???xBaxBi2Nb2O9 (x?=?0, 0.2, 0.4, 0.6, 0.8,... 相似文献
13.
The effects of inorganic nanoparticles on a conjugated polymer were investigated by measuring the electronic properties of poly(p-phenylene vinylene) (PPV) and PPV/Ag nanocomposites. Through hybridization, an enhancement in current density was achieved with PPV/Ag nanocomposites due to an increase in the electron affinity with Ag nanoparticle content. Furthermore, roughening of the surface morphology was observed with incorporation of Ag nanoparticles. This roughness induces an enhanced applied field at the thinner region of the film and an increase in the surface area with a resulting increase of electron injection, leading to current enhancement. 相似文献
14.
Sang-Bae Jung Tae-Jung Ha Hyung-Ho Park Haechoen Kim Won-Seon Seo Young Soo Lim 《Journal of Electroceramics》2010,25(2-4):140-144
Pseudomorphic high electron mobility transistors (PHEMTs) are promising devices for use in millimeter-wave and optical communications systems due to their excellent high frequency and low-noise performances. In order to further improve the performance of these devices, their gate lengths must be reduced to the technological limit and a small gate resistance must be realized. However, shorter gates result in an increase of short channel effects that limit microwave performance. In order to reduce the gate resistance, T-shaped gates with large cross-sectional areas are required. However, the thickness and dielectric constant of the passivation layer have major impacts on the gate capacitance. In this study, an ordered mesoporous silica film was introduced as a passivation layer between T-gates. Si3N4 with a dielectric constant of 7.4 and ordered mesoporous silica with a dielectric constant of 2.48 were used as passivation layers. The Si3N4 dielectric layer and the ordered mesoporous silica film were stacked together and the device characteristics were investigated. 相似文献
15.
Hyeong-Ho Park Hong-Sub Lee Hyung-Ho Park Xin Zhang Ross H. Hill 《Journal of Electroceramics》2010,24(3):214-218
Direct-patterned lead zirconate titanate (PZT) films prepared from an electron beam sensitive stock solution were investigated
for advanced stage applications in sub 50-nm patterned systems. The required electron beam dose for the direct-patterning
of PZT precursor films was 4.5 mC/cm2. The PZT precursor films with pattern size of 500 × 500 μm2 were exposed to an electron beam for 2 h and annealed at 400°C for 30 min under an O2 ambient. After exposure and annealing, values of the remnant polarization and coercive field were 7.0 μC/cm2 and 97 kV/cm at 10 V, respectively. These results suggest a possible application of PZT films in micro- or nano-electromechanical
systems. 相似文献
16.
The incorporation of SiO2 nanoparticles in poly(p-phenylenevinylene)(PPV) for PPV/SiO2 nanocomposite
The changes in surface morphology and current-voltage characteristics of poly(p-phenylenevinylene)(PPV) thin film has been studied by varying the amount of incorporated SiO2 nanoparticles. The electronic structure of carbon atom in PPV and PPV/SiO2 nanocomposite films was studied by using near-edge X-ray absorption fine structure. The surface morphology of PPV/SiO2 nanocomposite film was found to be greatly dependent on the amount of incorporated SiO2 nanoparticles. The current–voltage behavior of PPV/SiO2 nanocomposite film was mainly dependent on the surface morphology of the film. The excess content of SiO2 nanoparticles in PPV/SiO2 nanocomposite film was revealed to induce an agglomeration of SiO2 nanoparticles where blocking of electronic conduction happens. 相似文献
17.
Jin Yong Kim Hyeong-Ho Park A. Sivasankar Reddy Ho Jung Chang Hyeongtag Jeon Youngchul Chang Hyung-Ho Park 《Ceramics International》2008,34(4):1055-1058
In this paper, the effect of different sizes of Ag-nanoparticles dispersed in ZnO matrix using sol–gel method has been focused. Low-temperature crystallized ZnO thin films was achieved by sol–gel process, using zinc acetate dihydrate and 2-methoxyethanol as starting precursor and solvent, respectively. Various sizes of Ag-nanoparticles could be prepared by the spontaneous reduction method with changing the preparation temperatures and mole concentrations of Ag 2-ethylhexanoate in dimethyl sulfoxide solvent. The crystallographic structure of the Ag–ZnO hybrid film was analyzed by X-ray diffraction. Ag-nanoparticle size and optical property of Ag–ZnO hybrid films were measured by UV–vis spectrophotometer. 相似文献
18.
Poly(3,4-ethylenedioxythiophene) oxidized with poly(4-styrenesulfonate)(PEDOT:PSS) is a candidate material for applications
in molecular electronics, such as organic field effect devices, organic photovoltaics, and organic light emitting devices.
The properties of 3.5–4.0 nm sized SnO2 nanoparticles doped PEDOT:PSS films were investigated for anode application. Sheet resistance was decreased and rms roughness
was slightly increased with the incorporation of SnO2 nanoparticles. However, the connectivity of conducting grains was improved by the plasticizing effect of surface –OH groups
of SnO2 nanoparticle. Using photoemission spectroscopy and near edge X-ray absorption fine structure (NEXAFS), the electronic structure
of the films is studied comparatively on the C 1s NEXAFS, secondary electron emission cut off, and valence band spectra. The start of electron emission retarded and valence
band maximum was increased in the PEDOT:PSS-SnO2 nanocomposite films. These changes in the electronic structure resulted from emitted electron screening of core-hole in the
PEDOT:PSS energy band and electron donation of SnO2 nanoparticles. 相似文献
19.
Sin-Young Jung Tae-Jung Ha Won-Seon Seo Young Soo Lim Sangwoo Shin Hyung Hee Cho Hyung-Ho Park 《Journal of Electronic Materials》2011,40(5):652-656
Mesoporous materials have pores with diameters between 2 nm and 50 nm, the presence of which generally decreases the thermal
conductivity of the material. By incorporating mesoporous structures into thermoelectric materials, the thermoelectric properties
of these materials can be improved. Although TiO2 is an ordinary insulator, reduced TiO2 shows better electrical conductivity and is therefore a potential thermoelectric material. Furthermore, the addition of a
dopant to TiO2 can improve its electrical conductivity. We hypothesized that, by doping ordered mesoporous TiO2 films with niobium, we would be able to minimize the thermal conductivity and maximize the electrical conductivity. To investigate
the effects of Nb doping and a mesoporous structure on the thermoelectric characteristics of TiO2 films, Nb-doped mesoporous films were investigated using x-ray diffraction, ellipsometry, four-point probe measurements,
and thermal conductivity analysis. We found that Nb doping of ordered mesoporous TiO2 films improved their thermoelectric properties. 相似文献
20.
Superconducting YBa2Cu3O7–x
(YBCO) thin films were deposited onr-plane A12O3 substrates with PrBa2Cu3O7–x
(PBCO) buffer layer by XeCl excimer laser ablation. The thickness of PBCO buffer layer was systematically changed to investigate the superconducting properties of YBCO thin films on sapphire. The structure and surface morphology of the films were characterized by X-ray diffraction and scanning electron microscopy (SEM). Superconducting transition temperatures were varied depending on the buffer layer thickness. Interdiffusion between laser-ablated YBCO thin films and A12O3 substrates had been studied by Auger electron spectroscopy (AES). The results of this study show that diffusion does not occur between the YBCO thin film and the substrate even with 20 Å thick PBCO buffer layer. 相似文献