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1.
The role of substrates on the structural,optical, and morphological properties of zno nanotubes prepared by spray pyrolysis
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ZnO films were deposited onto glass, ITO coated glass, and sapphire substrate by spray pyrolysis, and subsequently annealed at the same temperature of 400°C for 3 h. The role of substrate on the properties of ZnO films was investigated. The structural and optical properties of the films were investigated by X‐ray diffractometer (XRD) and photoluminescence (PL) spectrophotometer, respectively. The surface morphology of the nanostructured ZnO film was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Crystallographic properties revealed that the ZnO films deposited on sapphire and ITO substrates exhibit a strong c‐axis orientation of grains with hexagonal wurtzite structure. Extremely high UV emission intensity was determined in the film on ITO. The different luminescence behaviors was discussed, which would be caused by least value of strain in the film. Films grown on different substrates revealed differences in the morphology. ZnO films on ITO and sapphire substrates revealed better morphology than that of the film on glass. AFM images of the films prepared on ITO show uniform distribution of grains with large surface roughness, suitable for application in dye sensitized solar cells. Microsc. Res. Tech. 77:211–215, 2014. © 2013 Wiley Periodicals, Inc. 相似文献
2.
E.-S. Yoon R.A. Singh H. Kong B. Kim D.-H. Kim H.E. Jeong K.Y. Suh 《Tribology Letters》2006,21(1):31-37
Nano-patterns made of poly(methyl methacrylate) (PMMA) were fabricated on silicon wafer using a capillarity-directed soft
lithographic technique. Patterns with three different aspect ratios were investigated for their adhesion and friction properties
at nano-scale and for friction at micro-scale. The patterned samples exhibited superior tribological properties, at both these
scales when compared to those of flat PMMA thin films. 相似文献
3.
Jason A. Bares Anirudha V. Sumant David S. Grierson Robert W. Carpick Kumar Sridharan 《Tribology Letters》2007,27(1):79-88
Small amplitude (50 μm) reciprocating wear of hydrogen-containing diamond-like carbon (DLC) films of different compositions
has been examined against silicon nitride and polymethyl-methacrylate (PMMA) counter-surfaces, and compared with the performance
of an uncoated steel substrate. Three films were studied: a DLC film of conventional composition, a fluorine-containing DLC
film (F-DLC), and silicon-containing DLC film. The films were deposited on steel substrates from plasmas of organic precursor
gases using the Plasma Immersion Ion Implantation and Deposition (PIIID) process, which allows for the non-line-of-sight deposition
of films with tailored compositions. The amplitude of the resistive frictional force during the reciprocating wear experiments
was monitored in situ, and the magnitude of film damage due to wear was evaluated using optical microscopy, optical profilometry, and atomic force
microscopy. Wear debris was analyzed using scanning electron microscopy and energy dispersive spectroscopy. In terms of friction,
the DLC and silicon-containing DLC films performed exceptionally well, showing friction coefficients less than 0.1 for both
PMMA and silicon nitride counter-surfaces. DLC and silicon-containing DLC films also showed significant reductions in transfer
of PMMA compared with the uncoated steel. The softer F-DLC film performed similarly well against PMMA, but against silicon
nitride, friction displayed nearly periodic variations indicative of cyclic adhesion and release of worn film material during
the wear process. The results demonstrate that the PIIID films achieve the well-known advantageous performance of other DLC
films, and furthermore that the film performance can be significantly affected by the addition of dopants. In addition to
the well-established reduction of friction and wear that DLC films generally provide, we show here that another property,
low adhesiveness with PMMA, is another significant benefit in the use of DLC films. 相似文献
4.
V. Podgursky T. Hantschel A. Bogatov E. Kimmari M. Antonov M. Viljus V. Mikli M. Tsigkourakos W. Vandervorst J. G. Buijnsters A. T. Raadik P. Kulu 《Tribology Letters》2014,55(3):493-501
The formation of nanoscopic ripple patterns on top of material surfaces has been reported for different materials and processes, such as sliding against polymers, high-force scanning in atomic force microscopy (AFM), and surface treatment by ion beam sputtering. In this work, we show that such periodic ripples can also be obtained in prolonged reciprocating sliding against nanocrystalline diamond (NCD) films. NCD films with a thickness of 0.8 µm were grown on top of silicon wafer substrates by hot-filament chemical vapor deposition using a mixture of methane and hydrogen. The chemical structure, surface morphology, and surface wear were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and AFM. The tribological properties of the NCD films were evaluated by reciprocating sliding tests against Al2O3, Si3N4, and ZrO2 counter balls. Independent of the counter body material, clear ripple patterns with typical heights of about 30 nm induced during the sliding test are observed by means of AFM and SEM on the NCD wear scar surfaces. Although the underlying mechanisms of ripple formation are not yet fully understood, these surface corrugations could be attributed to the different wear phenomena, including a stress-induced micro-fracture and plastic deformation, a surface smoothening, and a surface rehybridization from diamond bonding to an sp 2 configuration. The similarity between ripples observed in the present study and ripples reported after repeated AFM tip scanning indicates that ripple formation is a rather universal phenomenon occurring in moving tribological contacts of different materials. 相似文献
5.
Al、Sn掺杂对于ZnO薄膜微结构及光学特性的影响 总被引:2,自引:2,他引:0
采用真空电子束蒸发金属薄膜及后续热氧化技术在石英衬底上分别制备出了ZnO、Al∶ZnO以及Sn∶ZnO薄膜。通过X射线衍射仪(XRD),紫外-可见分光光度计和原子力显微镜(AFM)等分析仪器对比研究了Al、Sn掺杂对ZnO薄膜结晶质量、光学性质及表面形貌的影响。测试结果表明,Al、Sn掺杂可以使薄膜结晶质量得到提高,薄膜应力部分释放,薄膜表面的粗糙度也相应增加,掺杂对薄膜光学带隙的影响在一定程度取决于金属薄膜的氧化程度,氧化充分可以使光学带隙变宽,反之则变窄。 相似文献
6.
Myo Minn Motoyasu Kobayashi Hiroshi Jinnai Hirohmi Watanabe Atsushi Takahara 《Tribology Letters》2014,55(1):121-129
Due to their light weight, low corrosion and good tribological properties, polymer films have been widely studied in dry condition as well as recently in aqueous environment. Though the presence of water can further reduce the friction, it promotes the wear rate of the polymer films. As a remedy to decrease the wear rate of polymer films under aqueous condition, in this study, we used PMMA brush which is chemically anchored to a substrate and compared its friction and wear properties with those of conventional PMMA spin-cast film. Ellipsometry, contact angle measurements and atomic force microscopy are used to study the surface properties, e.g., wear mechanisms and wear depths of PMMA films. Under different sliding speeds and applied loads, PMMA brush showed lower friction than PMMA spin-cast film in aqueous. Moreover, it was shown that the swelling of water molecules is a dominant factor in determining the wear durability of PMMA films in which PMMA brush showed better wear performance than PMMA spin-cast film. 相似文献
7.
《Wear》1996,193(2):133-145
This paper presents the results of the characterisation of tribochemical films produced by the sliding wear of alumina in a humid environment. The techniques that were used were field emission scanning electron microscopy (FESEM) mechanical properties microprobe or nanoindentor (MPM), atomic force microscopy (AFM), frictional force microscopy (FFM) and non-contact optical profilometry.It was found that the tribochemical films were softer than the remnant alumina on the worn surfaces, and were liable to fracture and cracking under the indenter.The FESEM showed similar features to the AFM, but because of its direct height imaging, the AFM was better at resolving and imaging small MPM indentations. The AFM also showed that the tribochemical films were composed of small rounded particles which were pressed together to form the films.Some FFM contrast is attributed to steep gradients or edges, and some to variations in surface roughness. There is, however, some contrast which cannot easily be explained by simple geometric interactions and appears to be associated with variations in surface chemistry and structure. 相似文献
8.
采用“S”型磁过滤阴极弧等离子体沉积技术,室温下在(111)面单晶硅上沉积氮化钛薄膜。采用AFM和XRD技术分别对薄膜的表面形貌和晶体择优取向进行了表征,并用微刻划的方法分析薄膜的微观机械性能。结果表明,薄膜表面光滑致密,随偏压的增大,表面颗粒粒径先增大后减小,并且从(111)面的择优取向转变成(220)面。在刻划实验中,随载荷增加,薄膜先后经历了完全弹性变形,弹-塑性变形和脆性断裂阶段。利用直接和间接2种方法对得到的薄膜的临界载荷进行分析对比,发现在不同负偏压下,薄膜的内应力和临界载荷不同。随着负偏压的增大,薄膜的内应力逐渐增大,临界载荷逐渐减小。在-100V偏压下制备的氮化钛薄膜的微观机械性能最为理想。 相似文献
9.
Evidence is presented here for deposition kinetic energy influences on the wear properties of Au and Cu films deposited by
evaporation and sputtering on clean and poly(amidoamine) (PAMAM) dendrimer modified SiO
x
substrates. Ramped load nanoscratch tests show increased resistance to wear in the presence of the dendrimer monolayer. Nanoscratch
profiles indicate that the critical load to failure (scratch bearing capacity) is increased in the presence of a dendrimer
interlayer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis of the wear tracks show that following
film failure plowing is the predominant mechanism of wear for sputtered or evaporatively deposited Au. No obvious changes
in the wear properties (a pure cutting mechanism) of Cu thin films are observed upon changing the kinetic energy of the incoming
metal. 相似文献
10.
Dependence of the friction process on the molecular structure and architecture of thin polymer films
P.S. Thomas 《Tribology International》1996,29(8):631-637
The frictional properties of a homologous series of poly(n-alkyl methacrylates) (PnAMA) and a series of poly(methyl methacrylate) (PMMA) films, cast from a variety of solvents, are characterized. The choice of polymer film was driven by the consideration of the possible mechanisms for the accommodation of a macroscopically applied shear stress by molecular entities. Two possible mechanisms are proposed: (i) the relative flexibility of the polymer backbone chain. For this purpose the PnAMAs have been chosen. By varying the length of the substituent chain, the relative molecular freedom around the backbone chain is altered. These molecular differences are sensed in the frictional properties at the macroscopic level, and (ii) the molecular organization is also proposed to be a factor in determining the friction response of a particular polymer film. For this purpose, the frictional properties of PMMA films cast from different solvents are investigated. There is observed to be a strong influence of the molecular organization on the frictional properties of the solvent cast PMMA films. The molecular probe employed to characterize the molecular environment is vibrational spectroscopy. Conformationally sensitive vibrational modes are used to determine the relative flexibility of the backbone chain and the organization of the chain network. 相似文献
11.
Dependence of surface morphology on molecular structure and its influence on the properties of OLEDs
Most organic light-emitting diodes (OLEDs) have a multilayer structure composed of organic layers such as a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL) sandwiched between two electrodes. The organic layers are thin solid films with a thickness from a few nano meters to a few tenths nano meter, respectively. Surface morphology of an organic thin solid film in OLEDs depends on the molecular structure of the organic material and has an affect on device performance. To analyze the effect of surface morphology of an organic thin solid film on fluorescence and electroluminescence (EL) properties, thin solid films of 4-(dicyanomethylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran (DCM2) and new red fluorophores, (2E,2′E)-3,3′-[4,4″-bis(dimethylamino)-1,1′:4′,1″-terphenyl-2′,5′-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z,2′Z)-3,3′-[4,4″-bis(dimethylamino)-1,1′:4′,1″-terphenyl-2′,5′-diyl]bis(2-phenylacrylonitrile) (ABCV-P) were investigated by atomic force microscopy (AFM). The samples for EL and AFM measurement were fabricated by the high-vacuum thermal deposition (8×10−7 Torr) of organic materials onto the surface of indium tin oxide (ITO)-coated glass substrate, in which the layer structures of samples for AFM measurement and those for EL measurement were ITO/NPB (40 nm)/red emitters (80 nm) and ITO/NPB (40 nm)/red emitters (80 nm)/BCP (30 nm)/Liq (2 nm)/Al (100 nm), respectively. The analysis based on AFM measurements well supported that the photoluminescence properties and the device performance were very much dependent upon surface morphology of an organic thin layer. 相似文献
12.
Ramped load nanoscratch behaviors of titanium thin films with and without dendrimer mediation were extensively studied. By combining in situ investigation of scratch surface profiles and coefficients of friction curves, with ex situ microscopic (OM, AFM) and spectroscopic (AES) examinations of scratch tracks, different scratch failure modes were identified. An adhesive failure was found in the dendrimer-mediated films, whereas a cohesive failure was in the dendrimer-free samples. 相似文献
13.
In this paper we present recent results from an on‐going effort to characterize the nanomechanical properties of a variety
of tribochemical, antiwear films through the use of modern scanning probe techniques. The two types of antiwear wear films
studied, derived from zinc dialkyl dithiophosphate (alkyl ZDDP) and zinc diaryl dithiophosphate (aryl ZDDP), were chosen because
they possess significantly different wear characteristics. High resolution AFM topographic images showed significant differences
between the two types of films. More interestingly, high resolution imaging and quantitative mechanical properties testing
using the interfacial force microscope (IFM), revealed different elastic and plastic properties between the two types of films;
in addition each type of film possessed several distinct regions with respect to mechanical properties. The maximum values
for elastic modulus and hardness were located on the highly loaded regions of the alkyl ZDDP films which exhibited the best
tribological performance. In contrast, the aryl ZDDP films, which exhibited poorer antiwear behaviour, were devoid of such
resilient regions. Our results correlate the macroscopic wear behavior of the tribochemical films to differences in the mechanical
properties on a nanometer scale.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
The present study offers for the first time a correlation between static nanomechanical properties (nanohardness (H), elastic modulus (E), H/E and H
3/E
2 ratio) and dynamic properties (resulting from nanoscratch measurements) for Metal–ZrN thin films (Inconel–ZrN, Cr–ZrN and
Nb–ZrN) as well as monolayer polycrystalline ZrN thin films. Metal–ZrN thin films have a great industrial potential, as they
can combine high hardness with good elasticity and toughness making them effective for wear resistant application. Nanomechanical
and nanotribological properties of Metal–ZrN and ZrN thin films deposited by DC unbalanced magnetron sputtering were investigated
using an atomic force microscope interfaced with a Hysitron Triboscope. The elastic recovery of thin films under a normal
load applied during nanoindentation was evaluated and correlated with elastic recovery of thin films under dynamic loading
during nanoscratch measurements in order to asses which film compositions provide superior wear resistance. It is demonstrated
that dynamic elastic recovery measurements correlated well with those derived from static nanoindentation tests. The nanoscratch
test combines both normal and tangential loading, therefore, it is expected to be an even better predictor of wear-resistance.
The AFM nanoindentation and nanoscratch measurements show superior nanomechanical and nanotribological properties for Metal–ZrN
thin films when compared to polycrystalline ZrN thin films. 相似文献
15.
In this study, atomic force microscopy (AFM) imaging has been used to study the structural properties of polycrystalline CuInSe2 films, which are widely used as absorber materials in thin film solar cell devices. This technique demonstrated an excellent capability for the reproducible imaging of these rough polycrystalline materials. AFM imaging in combination with statistical analysis revealed distinct differences in the structural properties (i.e. grain width and height distributions, root‐mean‐square (RMS) and peak to valley (R(p–v)) roughness values) as a function of the specific growth technique used and the bulk composition of the films. In the case of Cu‐rich films, prepared by the H2Se/Ar treatment of Cu/In/Cu alloys, rough surface structures were in general observed. Statistical analysis revealed two distinct distribution of grains in these samples (1.0–2.5 μm and 3–5.5 μm) with large RMS and R(p–v) roughness values of 380 nm and 2.6 μm, respectively. In‐rich films were characterized by the presence of much smaller, roughly circular clusters with a significant reduction in both the width and height distributions as well as RMS and R(p–v) roughness values. The most successful growth techniques, in terms of producing homogeneous and dense films, were in the cases of H2Se/Ar treated metallic InSe/Cu/InSe alloys and the coevaporation of all materials to form CuInSe2. Both these techniques produced absorber films with very narrow grain width and height distributions as well as small roughness values. It was possible to establish that high efficiency devices are associated with the use of absorber films with narrow width distributions between 0.5 and 2 μm and small RMS (> 300 nm) roughness values. These values are used as a figure of merit in our laboratories to evaluate the structural properties of our CuInSe2 thin films. 相似文献
16.
Nanotribological characterization of molecularly thick lubricant films for applications to MEMS/NEMS by AFM 总被引:10,自引:0,他引:10
Molecularly thick perfluoropolyether (PFPE) films are considered to be good protective films for micro/nanoelectromechanical systems (MEMS/NEMS) to reduce stiction, friction, and improve their durability. Understanding the nanotribological performance and mechanisms of these films are quite important for efficient lubrication for MEMS/NEMS devices. These devices are used in various operating environments and their effect on friction, adhesion and durability needs to be clarified. For this purpose, mobile and chemically bonded PFPE films were deposited by dip coating technique. The friction and adhesion properties of these films were characterized by atomic force microscopy (AFM). The effect of rest time, velocity, relative humidity, and temperature on nanotribological properties of these films was studied. Durability of these films was also measured by repeated cycling tests. The adhesion, friction mechanisms of PFPE at molecular scale, and the mechanisms of the effect of operating environment and durability are subject of this paper. This study found that adsorption of water, formation of meniscus and its change during sliding, viscosity, and surface chemistry properties play a big role on the friction, adhesion, and durability of the lubricant films. 相似文献
17.
Atomic force microscopy (AFM) can be used to image cross-sections of thin-film samples. So far, however, it has mainly been used to study cross-sections of epitaxial systems or integrated circuits on crystalline substrates. In this paper, we show that AFM is a powerful tool to image fractured cross-sections of polycrystalline thin films deposited on crystalline and non-crystalline substrates, yielding unique information on the three-dimensional properties of the cross-sections, with a spatial resolution in the nm range. Original images of three different heterostructure systems are presented: Si(wafer)/SnO2/CdS/CdTe, glass/Mo/Cu(In,Ga)Se2,/CdS/ZnO, and glass/SnO2/WO3. We discuss the results by comparing AFM and scanning electron microscopy (SEM) images, and explain, for the different materials, why the AFM provides useful additional information. 相似文献
18.
Eun-Kyung Lee Chung-Gil Kang Sang-Mae Lee 《International Journal of Precision Engineering and Manufacturing》2010,11(3):461-468
It’s important to measure quantitative properties about the thermal-nano behavior of polymers in order to produce high quality
components using the nanoimprint lithography process. Nanoscale indentation can be used to make the cells for molecular electronics,
drug delivery, slots for integration into nanodevices and defects for tailoring both the structure and properties. In this
study, the formability of polymethylmetacrylate (PMMA) and polycarbonate (PC) were characterized. Thermo-mechanical properties
during formation at a high temperature. Polymers become softer at elevated temperature due to heating. In this case it is
particularly important to study the high temperature-induced mechanical properties of the polymer. Nanoindentation was used
to measure the thermo-mechanical properties of both PMMA and PC. The polymer was heated with the heating stage on a NanoXP.
For a CSM (Continuous Stiffness Method) mode test, the heating temperature was 110°C, 120°C, 130°C, 140°C and 150°C for the
PMMA, and 140°C, 150°C, 160°C, 170°C and 180°C for the PC. The maximum indentation depth for this test was 2000 nm. For the
basic mode test, the heating temperature was 90°C and 110°C for the PMMA, and 140°C and 160°C for the PC. The maximum loads
for this test were 10 mN, 20 mN and 40 mN. An indented pattern was also observed by using AFM. The pile-up phenomenon was
mitigated due to the indentation at elevated temperature but the sink-in phenomenon occurred in this instance. When patterning
at a high temperature, one should consider the variation in the indentation profile and depth after unloading when designing
a structure. It was thought that the mechanical properties decrease when the working temperature increases because PMMA and
PC are thermoplastics which soften or melt by heating. Further research in this area is required about the molecular weight
and molecular movement at elevated temperature when the free volume of molecules increases. 相似文献
19.
20.
Experimental study on physical properties of nanoporous anodic aluminum oxide by proton implantation
Yoon-Su Bae Jihoon Jeon Chan-Hee Jung Dukhyun Choi 《Journal of Mechanical Science and Technology》2014,28(8):3219-3222
Implantation is a promising method to control the surface characteristics by changing surface energy of target materials. Previously, polymer surfaces have been investigated for the change of their morphology and the corresponding contact angle after implantation. Furthermore, oxide thin films have been studied for how their surface properties are changed by implantation. However, nanoporous oxide materials have rarely explored for the effect of implantation. Here, we investigated the effects of proton implantation on morphological, mechanical, electrical, and surface properties of anodic aluminum oxide (AAO). We prepared nanoporous amorphous AAO films with different thicknesses (5 and 10 μm). Atomic force microscopy (AFM), contact angle (CA) measurements, two-probe electrical measurements, and nanoindentation were used to analyze the physical properties. By increasing fluences from 1015 to 1016 ions/cm2, CA is significantly changed up to about 40°, but the other properties hardly changed. 相似文献