共查询到20条相似文献,搜索用时 15 毫秒
1.
Pilkyu Kim Seung-Jae Moon Sungho Jeong 《Applied Physics A: Materials Science & Processing》2010,101(4):671-675
Crystallization of 100 nm thick amorphous silicon (a-Si) films deposited on glass substrates was carried out using a dual-green-laser method. Depending on a-Si deposition method, either low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD),
the density of impurities such as Al, K, and Na within the a-Si thin films significantly varied. For the high impurity case of LPCVD, grains of 200–300 nm in size were obtained, whereas
for the PECVD case a maximum grain size of about 4 μm was achieved, satisfying the requirements for applications in commercial
TFT devices. These results confirm that for the use of glass substrates in polycrystallization of a-Si, controlling the impurity density during substrate preparation is critical. 相似文献
2.
用透射电子显微镜(TEM)和x射线衍射(XRD)方法对经300℃,2h退火的Ag和Cu自由膜和Si基体上的Ag和Cu附着膜的异常晶粒生长和织构变化进行了实验研究.XRD分析表明:Ag和Cu沉积膜均有(111)和(100)择优取向.但经退火处理后,Ag和Cu自由膜的(111)织构稍有加强.相反,Si基体上的Ag和Cu附着膜的(100)和(110)织构明显加强,同时用TEM在Cu附着膜中观察到了两个(110)和四个(211)取向的异常大晶粒.根据表面能和应变能的各向异性对实验结果进行了分析. 相似文献
3.
K. Muthukkumaran P. Kuppusami R. Srinivasan K. Ramachandran E. Mohandas S. Selladurai 《Ionics》2007,13(1):47-50
Thermal properties of 15-mol% gadolinia doped ceria thin films (Ce0.85Gd0.15 O1.925) prepared by pulsed laser ablation on silicon substrates in the temperature range 473–973 K are presented. Thermal diffusivities
and thermal conductivities were evaluated using photoacoustic spectroscopy. The influence of grain size on thermal properties
of the films as a function of deposition temperature is studied. It is observed that the thermal diffusivity and the conductivity
of these films decreases up to 873 K and then increases with substrate temperatures. The thermal properties obtained in these
films are discussed on the basis of influence of grain size on phonon scattering. 相似文献
4.
T. F. Watson D. Belić P. Y. Convers E. J. Boyd S. A. Brown 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(1):81-85
Thin films produced by depositing tin clusters with sizes between 5 and 10 nm onto silicon nitride substrates were found to
be
highly coalesced resulting in grains with sizes ~30 nm. Exposing the clusters to nitrogen before they were deposited significantly
reduced the coalescence between them and resulted in granular films where the clusters mostly retained their shape. This is
due to a small
amount of tin nitride forming in the clusters. The coalesced and granular films were used to fabricate tin oxide gas sensors.
This was
done by depositing the two types of films onto silicon nitride chips and then oxidising them by baking at 250 °C for 24 h.
It was found that the sensors composed of uncoalesced clusters were much more sensitive to hydrogen. This was attributed to
the smaller grain size and the larger surface area of the granular films. 相似文献
5.
Pilkyu Kim Seung-Jae Moon Sungho Jeong 《Applied Physics A: Materials Science & Processing》2011,104(3):851-855
The effects of preheating laser power and pulse laser energy on the size and crystallinity of laterally grown grains by dual-laser
crystallization of amorphous silicon (a-Si) films on borosilicate glass substrates were investigated. Plasma-enhanced chemical
vapor deposition was adopted for the deposition of the a-Si films in order to reduce the process temperature and thus the
diffusion of metal impurities from the glass substrate to the deposited a-Si films. It was found that the preheating laser
power is critical in enhancing grain size, whereas the pulse laser energy is closely related to crystal quality. It is demonstrated
that by properly adjusting the process conditions, laterally grown grains of 50-μm size could be obtained. 相似文献
6.
Chang Woo Lee Choochon Lee Yong Tae Kim 《Applied Physics A: Materials Science & Processing》1993,56(2):123-126
Effects of multi-step rapid thermal annealing of plasma-deposited amorphous silicon films on Corning 7059 glass are investigated. A three-step rapid thermal annealing for 10 s/step at 730° C after film deposition reduces the activation energy of electrical conductivity for silicon films from 0.64 to 0.51 eV and causes (111) grain growth with a size of 1500 Å, which is determined using scanning electron microscopy, Raman spectroscopy and X-ray diffractometry. 相似文献
7.
B. M. Ayupov S. A. Prokhorova M. L. Kosinova Yu. M. Rumyantsev 《Optics and Spectroscopy》2012,112(2):201-205
The optical characteristics of nickel films deposited on Si(100) substrates by vacuum thermal evaporation have been studied.
The thickness and optical constants of the films are determined using monochromatic zero ellipsometry, while the inverse problems
are solved within the three-layer optical model of the samples. It is shown that thermal annealing leads to a change in the
optical constants of nickel films in the heating-temperature range of 500–900°C. Boron carbonitride layers deposited on silicon
substrates with a nickel sublayer are analyzed within multilayer optical models, which make it possible to determine the refractive
index and absorption coefficient distributions along the thickness of the synthesized Si(100)/Ni/BC
x
N
y
structure. 相似文献
8.
K. Rodrigo S. Heiroth N. Pryds L. Theil Kuhn V. Esposito S. Linderoth J. Schou T. Lippert 《Applied Physics A: Materials Science & Processing》2011,104(3):845-850
Ultrathin crystalline films of 10 mol% gadolinia-doped ceria (CGO10) are grown on MgO (100) substrates by pulsed laser deposition
at a moderate temperature of 400°C. As-deposited CGO10 layers of approximately 4 nm, 14 nm, and 22 nm thickness consist of
fine grains with dimensions ≤∼11 nm. The films show high density within the thickness probed in the X-ray reflectivity experiments.
Thermally activated grain growth, density decrease, and film surface roughening, which may result in the formation of incoherent
CGO10 islands by dewetting below a critical film thickness, are observed upon heat treatment at 400°C and 800°C. The effect
of the grain coarsening on the electrical characteristics of the layers is investigated and discussed in the context of a
variation of the number density of grain boundaries. The results are evaluated with regard to the use of ultrathin CGO10 films
as seeding templates for the moderate temperature growth of thick solid electrolyte films with improved oxygen transport properties. 相似文献
9.
Dinesh Pathak R. K. Bedi Davinder Kaur 《Applied Physics A: Materials Science & Processing》2009,95(3):843-847
AgInSe2 films were prepared by a thermal evaporation technique onto Si(100) substrates at a pressure of 10−5 mbar. Structural and optical properties of films deposited at 300 and 473 K have been investigated. The film composition
was studied by energy dispersive analysis through X-rays. X-ray diffraction patterns indicate that AgInSe2 films have chalcopyrite structure with strong preferred orientation in the (112) direction. Average vertical crystallite
size of 25 nm was observed. The optical energy gaps of 1.20 and 1.90 eV were obtained due to the fundamental absorption edge
and a transition originating from crystal field splitting, respectively. Field emission scanning electron microscopy shows
loosely packed grains of spherical symmetry with some facets. 相似文献
10.
Effect of microstructure on the thermoelectric properties of CSD-grown Bi2Sr2Co2Oy thin films 下载免费PDF全文
Three Bi2Sr2Co2Oy thin films with different microstructures have been prepared by chemical solution deposition on LaAlO 3(001) through varying the annealing temperature.With the decrease in the annealing temperature,both the size and c-axis alignment degree of grains in the film decrease as well,leading to an increase in the film resistivity.In addition,the decrease in the annealing temperature also results in a slight increase in the Seebeck coefficient due to the enhanced energy filtering effect of the small-grain film.The nanostructured Bi2Sr2Co2Oy film with an average grain size of about 100 nm shows a power factor comparable to that of films with larger grains.Since the thermal conductivity of the nanostructured films can be depressed due to the enhanced phonon scattering by grain boundary,a higher figure of merit is expected in Bi2Sr2Co2Oy thin film with grains in nanometer size. 相似文献
11.
M. F. Al-Kuhaili S. M. A. Durrani I. A. Bakhtiari 《Applied Physics A: Materials Science & Processing》2010,98(3):609-615
Thin films of molybdenum oxide were deposited in vacuum by pulsed laser ablation using a xenon fluoride (351 nm) and a krypton
fluoride (248 nm) excimer lasers. The films were deposited on unheated substrates and were post-annealed in air in the temperature
range 300–500°C. The structural, morphological, chemical, and optical properties of the films were studied. As-deposited films
were found to be dark. The transparency of the films was improved with annealing in air. The films were polycrystalline with
diffraction peaks that belong to the orthorhombic phase of MoO3. The surface morphology of the films showed a layered structure. Both the grain size and surface roughness increased with
annealing temperature. The stoichiometry of the films improved upon annealing in air, with the best stoichiometry of MoO2.95 obtained for films deposited by the XeF laser and annealed at 400°C. Similarly, the best transparency, with a transmittance
exceeding 80%, was obtained with the films annealed in the temperature range 400–450°C. 相似文献
12.
Rakesh Malik S. Annapoorni S. Lamba S. Mahmood R. S. Rawat 《Applied Physics A: Materials Science & Processing》2011,105(1):233-238
Nickel ferrite thin films were deposited by a pulsed laser deposition (PLD) technique on silicon substrate at room temperature
in a vacuum of 5×10−5 mbar. The films were subjected to different annealing temperatures from 300–900°C and were also exposed to single shot energetic
hydrogen ions using a Dense Plasma Focus (DPF) device. The changes induced in the films exposed at different distances from
the top of the anode were investigated. The structural, morphological and magnetic properties of the annealed and exposed
samples were investigated. X-ray diffraction (XRD) studies reveal the presence of a single phase of nickel ferrite after annealing.
SEM micrographs indicate an increase in the grain size, both on annealing as well as on exposure to hydrogen ions. Annealing
and hydrogen ion irradiation induced an enhancement in the magnetic moments. Laser droplets which are inherent in films deposited
by laser ablation were found to be dispersed as a result of single shot hydrogen ion irradiation from the DPF. 相似文献
13.
多晶硅在光电子器件领域具有较为重要的用途。利用磁控溅射镀膜系统,通过共溅射技术在玻璃衬底上制备了非晶硅铝(α-Si/Al)复合膜,将Al原子团包覆在α-Si基质中,膜中的Al含量可通过Al和Si的溅射功率比来调节。复合膜于N2气氛中进行350 ℃,10 min快速退火处理,制备出了多晶硅薄膜。利用X射线衍射仪、拉曼光谱仪和紫外-可见光-近红外分光光度计对多晶硅薄膜的性能进行表征,研究了Al含量对多晶硅薄膜性能的影响。结果表明:共溅射法制备的α-Si/Al复合膜在低温光热退火下晶化为晶粒分布均匀的多晶硅薄膜;随着膜中Al含量逐渐增加,多晶硅薄膜的晶化率、晶粒尺寸逐渐增加,带隙则逐渐降低;Al/Si溅射功率比为0.1时可获得纳米晶硅薄膜,Al/Si溅射功率比为0.3时得到晶化率较高的多晶硅薄膜,通过Al含量的调节可实现多晶硅薄膜的晶化率、晶粒尺寸及带隙的可控。 相似文献
14.
《Journal of Physics and Chemistry of Solids》2003,64(4):565-570
CdNiTe ternary semiconductor thin films were deposited using the cathodic erosion by radiofrequency technique (r.f. sputtering), on 7059 Corning glass substrates. Cd1−xNixTe targets with different Ni compositions in the range 0<x<0.15 were used. Structural analysis in these samples using SEM and X-ray diffraction have shown that films are polycrystalline with grain sizes between 26 and 35 nm; for higher Ni-content, films have smaller grain sizes. As-grown samples and thermal-annealed films in an inert atmosphere at temperatures of 300 and 400 °C were studied using the thermoreflectance spectroscopy (TR) at room temperature. From these measurements the bandgap energy variation as a function of the nanocrystallite size and the annealing temperatures was obtained. From the TR spectra a systematic shift to higher energies of the E0-point as the grain size decreases has been measured, and we have interpreted this result as due to the CdTe–Ni alloying process added to a quantum-size effect in which the nanocrystallites act as quantum dots. We discuss the TR lineshapes and their evolution with thermal annealing. 相似文献
15.
Tin oxide films have been prepared by oxidation of Sn thin films deposited by thermal evaporation method onto glass substrates. The oxidation of films was done, in air at a temperature of 500 °C, from 20 to 120 min. The oxidized films were characterized by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), photoluminescence spectroscopy (PL) and surface profilometer. The XRD patterns show that the crystalline structure of the oxidized Sn films improves with the annealing time. The tetragonal SnO2 phase (cassiterite) was obtained after 120 min of annealing with grains sizes between 15 and 20 nm. The thickness of oxide films, as function of the annealing time, follows a parabolic law. The O/Sn atomic ratio increases with the annealing time indicating an improvement of the films quality. Tin interstitials defects density, calculated from PL spectra using Smakula's formula, was found to decrease with the increasing annealing time. Tin interstitials defects density was found proportional to the increasing oxygen density (deduced from RBS). A fit of this proportionality allowed us to quantify the tin cations and oxygen anions diffused through the oxide films. 相似文献
16.
M. Thambidurai N. Muthukumarasamy N. Murugan Dhayalan Velauthapillai S. Agilan R. Balasundaraprabhu 《Applied Physics A: Materials Science & Processing》2011,104(4):1129-1136
Design of experiment (DOE) based on central composite design (CCD) has been employed for the development of a mathematical
model correlating the important process parameters like thiourea concentration (U), annealing temperature (A), rotational speed (S), and annealing time (T) of the spin coating process for the preparation of CdS thin films. The experiments were conducted as per the design matrix.
Nanocrystalline CdS thin films have been prepared using cadmium nitrate and thiourea as precursors by sol gel spin coating
method using the results of the mathematical model. The prepared CdS films have been characterized and the crystal structure
and grain size of the samples were analyzed using X-ray diffraction technique. The adequacy of the developed models was checked
by analysis of variance (ANOVA) technique. The accuracy of prediction has been carried out by conducting confirmation test.
Using this model, the main effect of process parameters on grain size of CdS films have been studied. These parameters were
optimized to obtain minimum grain size using the Microsoft excel solver. The results have been verified by depositing CdS
films using the optimized conditions. These films have been characterized using X-ray diffraction technique and the grain
size is found to be 8.8 nm. The high resolution transmission electron microscopy (HRTEM) analysis showed the grain size of
the prepared CdS film to be ∼7 nm. UV–vis spectroscopy analysis revealed that CdS films exhibited quantum confinement effect. 相似文献
17.
采用射频磁控溅射镀膜系统,在玻璃衬底上制备了非晶硅(α-Si)/铝(Al)复合薄膜,结合氮气(N2)气氛中低温快速光热退火制备了纳米晶硅(nc-Si)薄膜;利用光学显微镜、共焦光学显微仪、X射线衍射(XRD)仪、拉曼散射光谱(Raman)仪和紫外-可见光-近红外分光光度计(UV-VIS-NIR)对纳米晶硅薄膜的表面形貌、物相及光学性能进行了表征,研究了退火工艺对薄膜性能的影响。结果表明: 300 ℃,25 min光热退火可使α-Si/Al膜晶化为纳米晶硅薄膜,晶化率为15.56%,晶粒尺寸为1.75 nm;退火温度从300 ℃逐渐升高到400 ℃,纳米晶硅薄膜晶粒尺寸、晶化率、带隙逐渐增加,表面均匀性、晶格畸变量逐渐减小;退火温度从400 ℃逐渐升高到500 ℃,纳米晶硅薄膜的晶粒尺寸、晶化率继续增加,带隙则逐渐降低;采用纳米晶硅薄膜的吸光模型验证了所制备的纳米晶硅薄膜的光学特性,其光学带隙的变化趋势与吸光模型得出的结果一致。 相似文献
18.
V. A. Volodin A. S. Kachko A. G. Cherkov A. V. Latyshev J. Koch B. N. Chichkov 《JETP Letters》2011,93(10):603-606
Femtosecond laser treatments (second harmonic of Ti-sapphire laser, λ ≈ 400 nm wavelength, <30 fs pulse duration) were applied
for crystallization of thin hydrogenated amorphous silicon films on glass substrates. The concentration of atomic hydrogen
in the films was varied from 10 to ≈35%. The energy densities (laser fluences) for crystallization of the films with thicknesses
from 20 to 130 nm were found. Assumedly, non-thermal processes (plasma annealing) take place in phase transition caused ultra-fast
pulses. The developed approach can be used for creation of polycrystalline silicon films on non-refractory substrates. 相似文献
19.
Zinc oxide (ZnO) and Cu-doped ZnO (CZO) thin films were prepared on borosilicate glass substrates by spray pyrolysis technique.
The X-ray diffraction study revealed that Cu doping caused a reduction in crystallite size. AFM study showed an increase in
roughness with doping. This is attributed to the aggregation of particles to form clusters. From transmission electron microscopy
analysis, the particle size is measured to be in the range 30–65 nm (average particle size 48 nm) for undoped ZnO, whereas
it is in the range 24–56 nm (average particle size 40 nm) for CZO film. The electrical resistivity of the thin films was investigated
in the presence of air as well as N2 mixed air at different temperatures in the range 30–270 °C. The change in resistivity properties was explained on the basis
of conduction phenomena within the grain along with the grain boundaries as well as Cu- and N2-induced defect states. The thermal activation energy of ZnO was found to be in the range 0.04–0.7 eV and dependent on Cu
doping and N2 level in air. 相似文献
20.
Ahti Niilisk Mart Moppel Martti Pärs Ilmo Sildos Taavi Jantson Tea Avarmaa Raivo Jaaniso Jaan Aarik 《Central European Journal of Physics》2006,4(1):105-116
The Raman spectroscopy method was used for structural characterization of TiO2 thin films prepared by atomic layer deposition (ALD) and pulsed laser deposition (PLD) on fused silica and single-crystal
silicon and sapphire substrates. Using ALD, anatase thin films were grown on silica and silicon substrates at temperatures
125–425 °C. At higher deposition temperatures, mixed anatase and rutile phases grew on these substrates. Post-growth annealing
resulted in anatase-to-rutile phase transitions at 750 °C in the case of pure anatase films. The films that contained chlorine
residues and were amorphous in their as-grown stage transformed into anatase phase at 400 °C and retained this phase even
after annealing at 900 °C. On single crystal sapphire substrates, phase-pure rutile films were obtained by ALD at 425 °C and
higher temperatures without additional annealing. Thin films that predominantly contained brookite phase were grown by PLD
on silica substrates using rutile as a starting material. 相似文献