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

31 Jan 2011

Volume 98, Issue 5, Articles (05xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 98, 053101 (2011); http://dx.doi.org/10.1063/1.3549154 (3 pages)

Minggang Zeng, Lei Shen, Ming Yang, Chun Zhang, and Yuanping Feng
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Kinetics of ejected particles during breakdown in fused silica by nanosecond laser pulses

Rajesh N. Raman, Raluca A. Negres, and Stavros G. Demos

Appl. Phys. Lett. 98, 051901 (2011); http://dx.doi.org/10.1063/1.3549193 (3 pages) | Cited 3 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temporal evolution and kinetic properties of material particles ejected from the surface of fused silica under nanosecond laser irradiation are investigated using a time-resolved microscope system. The experiments provide information on the particle size, shape, and speed as a function of delay time, as well as on the duration of the material ejection process. The results suggest that the processes involved are much more complex than those predicted by current models.
Show PACS
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Ms Insulators
78.47.D- Time resolved spectroscopy (>1 psec)
79.20.Ds Laser-beam impact phenomena

Partial strain relaxation by stacking fault generation in InGaN multiple quantum wells grown on (1math01) semipolar GaN

Z. H. Wu, T. Tanikawa, T. Murase, Y.-Y. Fang, C. Q. Chen, Y. Honda, M. Yamaguchi, H. Amano, and N. Sawaki

Appl. Phys. Lett. 98, 051902 (2011); http://dx.doi.org/10.1063/1.3549561 (3 pages) | Cited 4 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the structural properties and relaxation phenomenon of InGaN multiple quantum wells (QWs) on (1math01) semipolar GaN templates grown on patterned (001) silicon substrates by selective area growth technique. Our studies by transmission electron microscopy and x-ray diffraction reciprocal space mapping reveal that QWs emitting light at 540 nm experience significant strain relaxation along the in-plane [1math0math] direction by the generation of an array of basal stacking faults (BSF). The generation of BSFs in 540 nm QWs could be an important factor limiting its luminescence efficiency.
Show PACS
68.65.Fg Quantum wells
61.72.Nn Stacking faults and other planar or extended defects
78.67.De Quantum wells

Ligament and joint sizes govern softening in nanoporous aluminum

A. C. To, J. Tao, M. Kirca, and L. Schalk

Appl. Phys. Lett. 98, 051903 (2011); http://dx.doi.org/10.1063/1.3549858 (3 pages) | Cited 2 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The present computational study demonstrates that softening of an open cell nanoporous aluminum structure subjected to tensile loading can be significantly reduced when the size of ligaments and the joints that connect them in the structure is designed to be sufficiently small. It is found using molecular dynamics simulations that the softening becomes slightly slower with increasing porosity for the structures with porosity less than or equal to 72%, and stress localization is observed during softening. In contrast, for structures with more than 75% porosity, softening is much slower, and stress delocalization occurs during softening. It is argued that at relatively high porosity, softening is governed by both the ligament size and the joint size because their compliance becomes high enough to allow the overloading stress due to ligament rupture to be redistributed more effectively throughout the structure.
Show PACS
61.43.Bn Structural modeling: serial-addition models, computer simulation
81.40.-z Treatment of materials and its effects on microstructure, nanostructure, and properties
61.46.-w Structure of nanoscale materials
61.43.Gt Powders, porous materials

Universal Ti-rich termination of atomically flat SrTiO3 (001), (110), and (111) surfaces

A. Biswas, P. B. Rossen, C.-H. Yang, W. Siemons, M.-H. Jung, I. K. Yang, R. Ramesh, and Y. H. Jeong

Appl. Phys. Lett. 98, 051904 (2011); http://dx.doi.org/10.1063/1.3549860 (3 pages) | Cited 8 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the surface termination of atomically flat SrTiO3 surfaces treated by chemical etching and subsequent thermal annealing, for all commercially available orientations (001), (110), and (111). Atomic force microscopy confirms that our treatment processes produce unit cell steps with flat terrace structures. We have also determined the topmost atomic layer of SrTiO3 surfaces through time-of-flight mass spectroscopy. We found that all three orientations exhibit a Ti-rich surface. Our observation opens doors for interface engineering along the [110] and [111] directions in addition to a well known [100] case, which widens the range of functional heterostructures and interfaces.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
81.40.Gh Other heat and thermomechanical treatments
68.37.Ps Atomic force microscopy (AFM)
82.80.Rt Time of flight mass spectrometry
68.35.bt Other materials

Transmission electron microscopy observations of dislocation annihilation and storage in nanograins

Lihua Wang, Ze Zhang, En Ma, and X. D. Han

Appl. Phys. Lett. 98, 051905 (2011); http://dx.doi.org/10.1063/1.3549866 (3 pages) | Cited 7 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A detailed in situ investigation of dislocation processes has been rare for nanograined materials with grain sized near or less than 10 nm. Here, we report a time-resolved and atomic-scale in situ transmission electron microscopy observation of the nucleation, motion, annihilation, and storage of full dislocations in nanograins with diameters less than ∼ 10 nm. Annihilation of dislocation dipoles appears to be a major contributor to the reduction in dislocation density, in addition to annihilation at grain boundary sinks. The accumulation of a high density of dislocations inside nanograins is found to be possible when they are surrounded by neighboring grains.
Show PACS
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.72.Mm Grain and twin boundaries
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Color center formation in vacuum sintered Nd3xY3−3xAl5O12 transparent ceramics

Adam J. Stevenson, Brad C. Bittel, Christopher G. Leh, Xin Li, Elizabeth C. Dickey, Patrick M. Lenahan, and Gary L. Messing

Appl. Phys. Lett. 98, 051906 (2011); http://dx.doi.org/10.1063/1.3549872 (3 pages) | Cited 4 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Color center formation was studied in vacuum sintered Nd3xY3−3xAl5O12 transparent ceramics. The primary color centers were F- and F+-centers as evidenced by optical absorption in the 250–400 nm wavelength range and the presence of an electron spin resonance (ESR) line at g = 1.9977. Annealing in air at 1600 °C for 10 h reduced the number of color centers to below the detection limit of ESR. Color center formation is controlled by oxidation and reduction of Fe2+/3+ impurities.
Show PACS
61.72.jn Color centers
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
78.40.Ha Other nonmetallic inorganics
76.30.Mi Color centers and other defects

Transmission electron microscopy of transparent conductive oxide films made by atmospheric pressure chemical vapor deposition

G. J. A. Mannie, J. van Deelen, J. W. Niemantsverdriet, and P. C. Thüne

Appl. Phys. Lett. 98, 051907 (2011); http://dx.doi.org/10.1063/1.3551523 (3 pages) | Cited 3 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The properties of crystalline films are strongly dependent on the morphology development during the first stages of growth, that is, the nucleation and growth of the first crystallites. The ideal method to investigate such films at atomic resolution is transmission electron microscopy (TEM). However, this technique usually requires extensive sample preparation. In this study we present a simple method to investigate thin film morphology with TEM. The key to this approach is the use of TEM membranes as growth substrates. As an illustration we describe fine grains of SnO2 deposited on these TEM membranes by atmospheric pressure chemical vapor deposition.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
68.55.J- Morphology of films

Improvement of UV emission from highly crystalline ZnO nanoparticles by pulsed laser ablation under O2/He glow discharge

Qiang Ma, Teguh Endah Saraswati, Akihisa Ogino, and Masaaki Nagatsu

Appl. Phys. Lett. 98, 051908 (2011); http://dx.doi.org/10.1063/1.3551534 (3 pages) | Cited 3 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Pulsed laser ablation under an O2/He glow discharge was studied to improve the surface crystallinity and UV luminescence of ZnO nanoparticles ∼ 10 nm in size. X-ray photoemission spectroscopy, scanning transmission electron microscopy, and cathodoluminescence spectroscopy were used to analyze the crystalline structures and chemical components. The results indicated that highly crystalline ZnO nanoparticles were fabricated under the O2/He plasma discharge. The near band gap UV emission intensities from these particles were roughly five times those of samples fabricated under O2 gas. The present results suggest the possibility of synthesize high quality ZnO quantum dots or nanoparticles without requiring any post-treatment.
Show PACS
81.07.Bc Nanocrystalline materials
81.16.Mk Laser-assisted deposition
81.05.Dz II-VI semiconductors
81.15.Fg Pulsed laser ablation deposition
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
68.65.Hb Quantum dots (patterned in quantum wells)

Intrinsic metastability of orthorhombic HfTiO4 in thin film hafnia-titania

Massiel Cristina Cisneros-Morales and Carolyn Rubin Aita

Appl. Phys. Lett. 98, 051909 (2011); http://dx.doi.org/10.1063/1.3551543 (3 pages) | Cited 2 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Orthorhombic (o) HfTiO4 is crystallized when sputter deposited hafnia-titania nanolaminates with ultrathin layers and bilayer (HfO2)0.5(TiO2)0.5 composition are annealed between 573 and 1173 K. However, o-HfTiO4 demixes after annealing at 1273 K, a result not predicted from bulk thermodynamics. X-ray diffraction and Raman microscopy are used here to study structural changes as o-HfTiO4 demixes upon long-term annealing at 1273 K into Ti-doped monoclinic HfO2 and Hf-doped rutile TiO2. We conclude that o-HfTiO4 crystallized at low temperature is intrinsically metastable. A space group symmetry analysis shows that demixing can be accomplished by a continuous phase transition chain.
Show PACS
64.70.K- Solid-solid transitions
81.40.Gh Other heat and thermomechanical treatments
81.15.Cd Deposition by sputtering
68.55.aj Insulators
64.75.Ef Mixing

Probing residual strain in epitaxial graphene layers on 4H-SiC(000math) with Raman spectroscopy

A. J. Strudwick, G. L. Creeth, N. A. B. Johansson, and C. H. Marrows

Appl. Phys. Lett. 98, 051910 (2011); http://dx.doi.org/10.1063/1.3551625 (3 pages) | Cited 7 times

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Raman microspectroscopy was used to measure compressive strain within epitaxial graphene (EG) grown on the carbon-terminated SiC(000math) face as a function of annealing time for a growth temperature of 1400 °C. A maximum strain of −0.5% was seen at the longest time of 55 min. This differs from the −0.9% expected for strain caused by cooling from the growth temperature due to the differential thermal contraction between the SiC and EG layer, despite good agreement between this model and data on EG on SiC(0001). We suggest that this is due to the different EG bonding mechanisms on the two SiC faces.
Show PACS
81.05.ue Graphene
68.65.Pq Graphene films
78.30.Na Fullerenes and related materials
81.15.Kk Vapor phase epitaxy; growth from vapor phase
78.67.Wj Optical properties of graphene
68.55.ap Fullerenes

Stress control during thermal annealing of copper interconnects

C.-C. Yang, C. Witt, P.-C. Wang, D. Edelstein, and R. Rosenberg

Appl. Phys. Lett. 98, 051911 (2011); http://dx.doi.org/10.1063/1.3551627 (3 pages)

Online Publication Date: 31 January 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Grain growth of Cu interconnects in an ultralow k dielectric was achieved at an elevated anneal temperature of 300 °C without stress voiding related problems. For this, a TaN metal passivation layer was deposited on the Cu interconnect surface prior to the thermal annealing process, which suppressed void formation within the Cu features during the anneal process and reduced inelastic deformation within the interconnects after cooling down to room temperature. As compared to the conventional anneal process at 100 °C, the passivation layer enabled further Cu grain growth at elevated temperatures, which then resulted in lower electrical resistance in the Cu interconnects.
Show PACS
85.40.Ls Metallization, contacts, interconnects; device isolation

Structural and elemental characterization of high efficiency Cu2ZnSnS4 solar cells

Kejia Wang, Byungha Shin, Kathleen B. Reuter, Teodor Todorov, David B. Mitzi, and Supratik Guha

Appl. Phys. Lett. 98, 051912 (2011); http://dx.doi.org/10.1063/1.3543621 (3 pages) | Cited 20 times

Online Publication Date: 1 February 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have carried out detailed microstructural studies of phase separation and grain boundary composition in Cu2ZnSnS4 based solar cells. The absorber layer was fabricated by thermal evaporation followed by post high temperature annealing on hot plate. We show that inter-reactions between the bottom molybdenum and the Cu2ZnSnS4, besides triggering the formation of interfacial MoSx, results in the out-diffusion of Cu from the Cu2ZnSnS4 layer. Phase separation of Cu2ZnSnS4 into ZnS and a Cu–Sn–S compound is observed at the molybdenum-Cu2ZnSnS4 interface, perhaps as a result of the compositional out-diffusion. Additionally, grain boundaries within the thermally evaporated absorber layer are found to be either Cu-rich or at the expected bulk composition. Such interfacial compound formation and grain boundary chemistry likely contributes to the lower than expected open circuit voltages observed for the Cu2ZnSnS4 devices.
Show PACS
88.40.hj Efficiency and performance of solar cells
88.40.jn Thin film Cu-based I-III-VI2 solar cells

Real-time direct observation of Li in LiCoO2 cathode material

Rong Huang, Taro Hitosugi, Scott D. Findlay, Craig A. J. Fisher, Yumi H. Ikuhara, Hiroki Moriwake, Hideki Oki, and Yuichi Ikuhara

Appl. Phys. Lett. 98, 051913 (2011); http://dx.doi.org/10.1063/1.3551538 (3 pages) | Cited 15 times

Online Publication Date: 1 February 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The direct observation of light elements such as Li is a challenge even for state-of-the-art electron microscopy techniques because such elements scatter electrons only weakly. Using the annular bright field scanning transmission electron microscopy imaging technique, we have simultaneously visualized columns of Li, O, and Co ions in the lithium-ion battery cathode material LiCoO2, which is one of the most important cathode materials for industrial applications. The annular bright field image exhibits a good signal-to-noise ratio and the image contrast is not reversed as the specimen thickness changes. The direct visualization of light elements in real time with this method represents an important breakthrough in characterizing the active materials in solid-state electrochemical devices.
Show PACS
88.80.ff Batteries
82.47.Aa Lithium-ion batteries
82.45.Fk Electrodes

Vibrational properties of graphene fluoride and graphane

H. Peelaers, A. D. Hernández-Nieves, O. Leenaerts, B. Partoens, and F. M. Peeters

Appl. Phys. Lett. 98, 051914 (2011); http://dx.doi.org/10.1063/1.3551712 (3 pages) | Cited 12 times

Online Publication Date: 2 February 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The vibrational properties of graphene fluoride and graphane are studied using ab initio calculations. We find that both sp3 bonded derivatives of graphene have different phonon dispersion relations and phonon densities of states as expected from the different masses associated with the attached atoms of fluorine and hydrogen, respectively. These differences manifest themselves in the predicted temperature behavior of the constant-volume specific heat of both compounds.
Show PACS
63.22.Rc Phonons in graphene
63.20.dk First-principles theory
65.80.Ck Thermal properties of graphene

Structural and electronic characterization of (2,33) bar-shaped stacking fault in 4H-SiC epitaxial layers

Massimo Camarda, Andrea Canino, Antonino La Magna, Francesco La Via, G. Feng, T. Kimoto, M. Aoki, and H. Kawanowa

Appl. Phys. Lett. 98, 051915 (2011); http://dx.doi.org/10.1063/1.3551542 (3 pages) | Cited 3 times

Online Publication Date: 4 February 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Crystallographic, electronic, and energetic analyses of the (2,33) [or (2,3,3,3) in the standard Zhadanov notation] bar-shaped stacking fault, observed in as-grown 4H-SiC epitaxial layers, are presented. The defect has been identified by means of spatially resolved microphotoluminescence (μ-PL) measurements at different emission wavelengths, focusing on the emission peak at 0.3 eV below the conduction band. Low temperature μ-PL measurements have also been performed. The defect has been identified and characterized using high resolution transmission electron microscopy. Experimental results are correlated and validated by the calculations of the Kohn–Sham electronic band structure and the defect formation energy.
Show PACS
71.20.Nr Semiconductor compounds
78.55.Hx Other solid inorganic materials
61.72.Nn Stacking faults and other planar or extended defects
78.66.Li Other semiconductors
71.55.Ht Other nonmetals
68.37.Og High-resolution transmission electron microscopy (HRTEM)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close