APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

7 Feb 2005

Volume 86, Issue 6, Articles (06xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 86, 063101 (2005); http://dx.doi.org/10.1063/1.1861133 (3 pages)

Choongho Yu, Qing Hao, Sanjoy Saha, Li Shi, Xiangyang Kong, and Z. L. Wang
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Two-dimensional growth of continuous Cu2O thin films by magnetron sputtering

Z. G. Yin, H. T. Zhang, D. M. Goodner, M. J. Bedzyk, R. P. H. Chang, Y. Sun, and J. B. Ketterson

Appl. Phys. Lett. 86, 061901 (2005); http://dx.doi.org/10.1063/1.1861117 (3 pages) | Cited 9 times

Online Publication Date: 31 January 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present results on the in situ, two-dimensional growth (as opposed to the more commonly encountered island-coalescence mechanism) of continuous epitaxial Cu2O films on MgO(011) using dc facing-magnetron sputtering from metallic Cu targets in an oxygen/argon atmosphere. Film growth was studied as a function of deposition time and the dc power applied to the guns. Control of the latter leads to either continuous or island-/rodlike film morphologies.
Show PACS
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.15.Cd Deposition by sputtering
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.35.B- Structure of clean surfaces (and surface reconstruction)

Fabrication and optical properties of two-dimensional photonic crystals of CdSe pillars

L. M. Chuang, H. K. Fu, and Y. F. Chen

Appl. Phys. Lett. 86, 061902 (2005); http://dx.doi.org/10.1063/1.1856136 (3 pages) | Cited 8 times

Online Publication Date: 31 January 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The combination of electron beam lithography and electrochemical deposition has been employed to fabricate well-controlled submicrometer-scale CdSe pillars. The formation of the wurtzite crystal structure of CdSe pillars has been confirmed by x-ray diffraction and Raman spectra. Quite interestingly, we found that the intensity of micro-photoluminescence can be greatly enhanced at the specially designed two-dimensional photonic crystals (PCs) based on Maxwell’s equations. This peculiar phenomenon can be explained quite well in terms of the effects of PCs. PCs can provide a photonic bandgap for the emission in the lateral dimensions so that the emission of CdSe pillars cannot propagate in the lateral plane and can only propagate upward with respect to PCs. Besides, PCs can also provide a pathway for the phase match between guided modes and radiation modes to avoid total internal reflection. Thus, the detected PL intensity normal to the lateral plane can be greatly enhanced.
Show PACS
42.82.Cr Fabrication techniques; lithography, pattern transfer
85.40.Hp Lithography, masks and pattern transfer
81.15.Pq Electrodeposition, electroplating
42.79.-e Optical elements, devices, and systems
42.70.Qs Photonic bandgap materials
78.55.Et II-VI semiconductors
78.30.Fs III-V and II-VI semiconductors

Large optical power limiting from self-assembly organic complexes

Zhi Yang, Zhikun Wu, Jinshi Ma, Andong Xia, Quanshui Li, Chunling Liu, and Qihuang Gong

Appl. Phys. Lett. 86, 061903 (2005); http://dx.doi.org/10.1063/1.1857089 (3 pages) | Cited 9 times

Online Publication Date: 31 January 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical properties of several synthesized complexes formed by self-assembly of pyrrol-2-yl-methyleneamines with zinc (II) ions are reported. Using a nanosecond optical parametric oscillator as the laser source, strong broadband optical power limiting performances based on two-photon absorption (TPA) have been observed in the visible region, where these materials exhibit large two-photon absorption (TPA) cross sections from 10−18 to 10−16 cm4/GW in chloroform solution.
Show PACS
42.70.Jk Polymers and organics
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Me Organic compounds and polymers

Upconversion photoluminescence in poly(ladder-type-pentaphenylene) doped with metal (II)-octaethyl porphyrins

S. Baluschev, P. E. Keivanidis, G. Wegner, J. Jacob, A. C. Grimsdale, K. Müllen, T. Miteva, A. Yasuda, and G. Nelles

Appl. Phys. Lett. 86, 061904 (2005); http://dx.doi.org/10.1063/1.1857073 (3 pages) | Cited 22 times

Online Publication Date: 31 January 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the optimization of the upconversion photoluminescence in films of conjugated polymers doped with platinum porphyrin. The upconversion emission was observed to take place at pump intensities as low as 0.5 kW/cm2. Comparison between the photoluminescence integral intensity of polyfluorene and ladder-type pentaphenylene polymer shows a five-fold increase of the efficiency of the upconversion process for the latter. The higher upconversion efficiency can be partially attributed to the reduced reabsorption of the photoluminescence in the case of the ladder-type pentaphenylene matrix.
Show PACS
78.66.Qn Polymers; organic compounds
78.55.Kz Solid organic materials

Resonant Raman scattering in strained and relaxed InGaN/GaN multi-quantum wells

S. Lazić, M. Moreno, J. M. Calleja, A. Trampert, K. H. Ploog, F. B. Naranjo, S. Fernandez, and E. Calleja

Appl. Phys. Lett. 86, 061905 (2005); http://dx.doi.org/10.1063/1.1861496 (3 pages) | Cited 6 times

Online Publication Date: 1 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of the composition and strain in InGaN/GaN multi-quantum wells on their phonon frequencies have been determined using resonant Raman scattering in a wide energy range. In pseudomorphic quantum wells a strong compensation of both effects occurs, resulting in the InGaN A1LO phonon frequency being almost independent on In concentration. In relaxed quantum wells the A1LO frequency is clearly below the GaN value and depends on the excitation energy, as reported in thick films. This variation, together with the resonance profile, gives a direct estimate of the In concentration and its fluctuations.
Show PACS
68.65.Fg Quantum wells
78.67.De Quantum wells
78.30.Fs III-V and II-VI semiconductors
78.55.Cr III-V semiconductors
61.72.S- Impurities in crystals
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
68.35.Gy Mechanical properties; surface strains
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances

Identifying materials with low friction and adhesion for nanotechnology applications

Nikhil S. Tambe and Bharat Bhushan

Appl. Phys. Lett. 86, 061906 (2005); http://dx.doi.org/10.1063/1.1856688 (3 pages) | Cited 4 times

Online Publication Date: 1 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The advent of micro/nanostructures and the subsequent miniaturization of moving components for various nanotechnology applications have ascribed paramount importance to tribology and mechanics on the nanoscale. Materials with low friction and adhesion are desirable for avoiding premature failures. We present the coefficient of friction and adhesion dependence on the Young’s modulus over a range of sliding velocities for an array of materials. A contour map is developed to identify tribologically suitable materials. This approach provides a fundamental insight into the mechanical property dependence of friction and adhesion and simplifies the material selection process for nanotechnology applications.
Show PACS
62.25.-g Mechanical properties of nanoscale systems
81.40.Pq Friction, lubrication, and wear
68.35.Gy Mechanical properties; surface strains
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.Qp Friction, tribology, and hardness
62.20.D- Elasticity

Parameter for glass forming ability of ternary alloy systems

E. S. Park, D. H. Kim, and W. T. Kim

Appl. Phys. Lett. 86, 061907 (2005); http://dx.doi.org/10.1063/1.1862790 (3 pages) | Cited 26 times

Online Publication Date: 2 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A parameter (σ parameter) for glass forming ability (GFA) of the ternary bulk metallic glasses is proposed, taking into consideration the relative thermodynamic stability and atomic configuration of the liquid phase. The σ parameter, defined by ΔT*×P′, combines the effects of melting temperature depression (ΔT*) and effective atomic size mismatch between constituting elements (P′). The parameter shows better correlation with GFA than previously proposed parameters. The relationship between σ and GFA can be expressed as Dmax = 2.0×10−1 exp(20.01 σ), where Dmax is the maximum thickness for glass formation. Since σ can be calculated simply using data on melting temperature and atomic size, the GFA can be easily estimated using this parameter.
Show PACS
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
64.70.D- Solid-liquid transitions
61.43.Fs Glasses

Optical properties of single-crystalline α-Si3N4 nanobelts

Ligong Zhang, Hua Jin, Weiyou Yang, Zhipeng Xie, Hezhuo Miao, and Linan An

Appl. Phys. Lett. 86, 061908 (2005); http://dx.doi.org/10.1063/1.1862753 (3 pages) | Cited 26 times

Online Publication Date: 3 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical properties of single-crystalline α-Si3N4 nanobelts synthesized via catalyst-assisted pyrolysis of polymeric precursor were characterized by absorption, photoluminescence (PL) and photoluminescence excitation (PLE). The optical absorption spectrum showed that the nanobelts exhibited indirect absorption behavior with optical band gap of ∼ 5.0 eV. Three broad peaks centered at 1.8, 2.3, and 3.0 eV were observed from the room-temperature PL spectrum of the nanobelts. The PLE spectra suggested the existence of multifold energy levels within the gap. A qualitative model was proposed to explain the observed absorption, PL and PLE spectra.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.55.Hx Other solid inorganic materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Direct evidence for compressive elastic strain at ground surfaces of nanocomposite ceramics

B. K. Tanner, H. Z. Wu, and S. G. Roberts

Appl. Phys. Lett. 86, 061909 (2005); http://dx.doi.org/10.1063/1.1862754 (3 pages) | Cited 1 time

Online Publication Date: 3 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-resolution grazing incidence x-ray powder diffraction has been used to provide direct evidence for the existence of a uniform compressive strain close to the surface of ground alumina∕SiC nanocomposites. No such strain is found in ground surfaces of single-phase alumina or polished surfaces of nanocomposite. The strain in the ground nanocomposite is found to be perpendicular to the grinding direction and disappears on annealing at 1250 °C. Such a compressive stress provides a mechanism for enhancing the strength of the nanocomposite, by opposing any tensile loading tending to open surface flaws. The origin of the stresses probably lies in the enhanced grain boundary strength in the nanocomposite alumina–silicon carbide compared to alumina.
Show PACS
81.05.Mh Cermets, ceramic and refractory composites
81.07.Bc Nanocrystalline materials
81.40.Lm Deformation, plasticity, and creep
68.35.Gy Mechanical properties; surface strains
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Gh Other heat and thermomechanical treatments
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.65.Ps Polishing, grinding, surface finishing
62.20.D- Elasticity
62.20.M- Structural failure of materials
62.20.F- Deformation and plasticity
61.72.Mm Grain and twin boundaries

Quantitative high-pressure pair distribution function analysis of nanocrystalline gold

C. David Martin, Sytle M. Antao, Peter J. Chupas, Peter L. Lee, Sarvjit D. Shastri, and John B. Parise

Appl. Phys. Lett. 86, 061910 (2005); http://dx.doi.org/10.1063/1.1856691 (3 pages) | Cited 10 times

Online Publication Date: 3 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using a diamond anvil cell with high-energy monochromatic x rays, we have studied the total scattering of nanocrystalline gold to 20 Å−1 at pressures up to 10 GPa in a hydrostatic alcohol pressure-medium. Through direct Fourier transformation of the structure function [S(Q)], pair distribution functions (PDFs) [G(r)] are calculated without Kaplow-type iterative corrections. Quantitative high-pressure PDF (QHP-PDF) analysis is performed via full-profile least-squares modeling and confirmed through comparison of Rietveld analysis of Bragg diffraction. The quality of the high pressure PDFs obtained demonstrates the integrity of our technique and suggests the feasibility of future QHP-PDF studies of liquids, disordered solids, and materials at phase transition under pressure.
Show PACS
61.46.-w Structure of nanoscale materials
78.70.Ck X-ray scattering
62.50.-p High-pressure effects in solids and liquids
61.43.Bn Structural modeling: serial-addition models, computer simulation

Why is the band model not contradictory to molecular theory in organic electroluminescence?

Zheng Xu, Chong Qu, Feng Teng, Fujun Zhang, Lijian Meng, and Xurong Xu

Appl. Phys. Lett. 86, 061911 (2005); http://dx.doi.org/10.1063/1.1861134 (3 pages) | Cited 10 times

Online Publication Date: 4 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In organic electroluminescence there is a sharp contradiction between the applicability of band model and molecular theory. This contradiction arose from the very beginning of extended study. In this report we studied the blue spectral shift in the newly discovered solid state cathodoluminescence when the applied voltage is increased. There are three different kinds of spectra in three intervals of applied voltage. The reason of this spectral shift is found to be the field ionization of exciton. The switching on of recombination starts only after the beginning of this field ionization. The exciton emission obeys molecular theory and the recombination obeys band model. Thus the demarcation is the appearance of field ionization of excitons. Since the ionization changes with electric field continuously, there is a region of coexistence of these two processes.
Show PACS
78.60.Fi Electroluminescence
78.60.Hk Cathodoluminescence, ionoluminescence
78.55.Kz Solid organic materials
79.70.+q Field emission, ionization, evaporation, and desorption
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Reorientation of the H2O cage studied by terahertz time-domain spectroscopy

B. L. Yu, Y. Yang, F. Zeng, X. Xin, and R. R. Alfano

Appl. Phys. Lett. 86, 061912 (2005); http://dx.doi.org/10.1063/1.1862788 (3 pages) | Cited 6 times

Online Publication Date: 4 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The terahertz absorption spectrum of a thin film of liquid H2O of ∼ 14 μm thickness showed a clear absorption mode at 1.56 THz ( ∼ 53 cm−1). This mode is attributed to the bending motion of the intermolecular hydrogen-bond coordinate in a water cage. The dielectric relaxation times of a slow τ1 ∼ 9 ps and a fast τ2 ∼ 0.2 ps component (0.4–2.0 THz) were determined using a double Debye dielectric model.
Show PACS
77.84.Nh Liquids, emulsions, and suspensions; liquid crystals
77.55.-g Dielectric thin films
68.15.+e Liquid thin films
78.70.Gq Microwave and radio-frequency interactions
77.22.Gm Dielectric loss and relaxation
77.22.Ch Permittivity (dielectric function)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Atomic dynamics in molecular dynamics simulations of glassy CuTi thin films

Sebastian Vauth and S. G. Mayr

Appl. Phys. Lett. 86, 061913 (2005); http://dx.doi.org/10.1063/1.1861982 (3 pages) | Cited 4 times

Online Publication Date: 4 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present results on atomic dynamics in metallic glass thin films below the glass transition temperature using molecular dynamics simulations. Thin CuTi films of different compositions are prepared by quenching the liquid to an amorphous state. The atomic dynamics on the amorphous surface and inside the bulk of the samples are quantitatively compared by calculating diffusion constants and jump length distributions. Here, we focus on the collective or single particle character of the diffusion mechanism in dependence of the atom type. In addition, single atom exemplifications are analyzed for the different kinds of atomic dynamics. We find that Cu surface atoms diffuse with a single atom jump dynamics, whereas inside the bulk collective behavior dominates for both species.
Show PACS
61.43.Fs Glasses
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
61.43.Bn Structural modeling: serial-addition models, computer simulation
68.35.Fx Diffusion; interface formation
81.05.Kf Glasses (including metallic glasses)
66.30.Dn Theory of diffusion and ionic conduction in solids
81.40.Gh Other heat and thermomechanical treatments

Nondestructive characterization of dislocations and micropipes in high-resistivity 6H–SiC wafers by deep-level photoluminescence mapping

M. Tajima, E. Higashi, T. Hayashi, H. Kinoshita, and H. Shiomi

Appl. Phys. Lett. 86, 061914 (2005); http://dx.doi.org/10.1063/1.1862330 (3 pages) | Cited 11 times

Online Publication Date: 4 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrated the effectiveness of deep-level photoluminescence (PL) mapping for nondestructive detection of dislocations and micropipes in high-resistivity 6H–SiC wafers. PL spectra of the wafers at room temperature were dominated by a broad band with a peak at 1.3 eV, which was traceable to the Si vacancy-related V1, V2, and V3 lines at 4.2 K. The intensity-mapping pattern agreed closely with the etch-pit pattern both on a wafer scale and on a microscopic scale. Large dark spots with one or two bright cores, small dark spots, and dark lines corresponded to micropipes, threading screw dislocations, and edge dislocations forming small angle grain boundaries, respectively. The intensity reduction around dislocations and micropipes was attributed to a decrease of the radiative centers for the 1.3 eV band, which occurred as a result either of the interaction between vacancies and dislocations or of the gettering effect of vacancy-related defects.
Show PACS
81.70.Fy Nondestructive testing: optical methods
61.72.Yx Interaction between different crystal defects; gettering effect
81.05.Hd Other semiconductors
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
78.55.Hx Other solid inorganic materials
61.72.J- Point defects and defect clusters
61.72.Mm Grain and twin boundaries

Perylene monolayer on the Ru(0001) surface

B. Lu, H. J. Zhang, Y. S. Tao, H. Huang, H. Y. Li, S. N. Bao, P. He, and Q. Chen

Appl. Phys. Lett. 86, 061915 (2005); http://dx.doi.org/10.1063/1.1862341 (3 pages) | Cited 6 times

Online Publication Date: 4 February 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The growth of epitaxial monolayer of perylene on Ru(0001) was investigated by means of scanning tunneling microscopy (STM). The STM images showed a coexistence of the ordered phase with a 12×12 superstructure and the disordered phase in a monolayer of perylene on Ru(0001). In the disordered region, the perylene molecules are randomly distributed, and orientated uniformly with their long axis in the [1000] direction. For the ordered phase, a model of the Ru(0001)-(12×12)-8 perylene superstructure was proposed. The results indicate that the growth behavior of perylene on Ru(0001) is mainly controlled by laterally repulsive molecule-molecule interaction.
Show PACS
81.05.Hd Other semiconductors
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
61.43.Dq Amorphous semiconductors, metals, and alloys
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.35.B- Structure of clean surfaces (and surface reconstruction)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close