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22 Jan 2007

Volume 90, Issue 4, Articles (04xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 90, 043507 (2007); http://dx.doi.org/10.1063/1.2435508 (3 pages)

D. Y. Kim and A. J. Steckl
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Detection of coherent acoustic oscillations in a quantum electromechanical resonator

Florian W. Beil, Robert H. Blick, Achim Wixforth, Werner Wegscheider, Dieter Schuh, and Max Bichler

Appl. Phys. Lett. 90, 043101 (2007); http://dx.doi.org/10.1063/1.2432954 (3 pages) | Cited 2 times

Online Publication Date: 22 January 2007

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Coherent control of occupation numbers in quantum mechanical multilevel systems is widely studied driven by its application in lasers and its prospects for quantum computational elements. Here the authors present a nanoelectromechanical resonator equivalent to the coherent control of a quantum mechanical two level system. The distinct eigenmodes of a nanomechanical beam resonator represent the two levels whose amplitude mode occupation numbers are controlled by a frequency matched acoustic excitation, mediated by a pulsed surface acoustic wave. They show that similar to quantum mechanical systems it is possible to transfer occupation numbers from one mode to another by matched acoustic pulses.
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43.35.Sx Acoustooptical effects, optoacoustics, acoustical visualization, acoustical microscopy, and acoustical holography
03.67.Lx Quantum computation architectures and implementations

Micro-Raman spectroscopy of a single freestanding GaN nanorod grown by molecular beam epitaxy

Ching-Lien Hsiao, Li-Wei Tu, Tung-Wei Chi, Min Chen, Tai-Fa Young, Chih-Ta Chia, and Yu-Ming Chang

Appl. Phys. Lett. 90, 043102 (2007); http://dx.doi.org/10.1063/1.2433034 (3 pages) | Cited 18 times

Online Publication Date: 22 January 2007

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Micro-Raman spectra were measured on a single freestanding GaN nanorod, which was grown by molecular beam epitaxy. A sharp linewidth of E2(high) mode of 2.1 cm−1 measured in the x(y,y)math configuration indicates the high crystalline quality of the nanorod. The angle-dependent Raman spectroscopy shows that the integrated intensities of these first-order Raman modes follow the theoretical sinusoidal functions. The forbidden E1(LO) mode that appeared in the x(z,z)math scattering configurations is assigned to the quasi-LO phonon mode. Power-dependent Raman spectroscopy shows redshift with increasing laser power density due to sample heating which is confirmed by Stokes and anti-Stokes measurements. The broadband centered at 708.5 cm−1 is ascribed to the surface mode of the nanostructure.
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78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.30.Fs III-V and II-VI semiconductors
61.46.Hk Nanocrystals
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
81.40.Gh Other heat and thermomechanical treatments

Pulsed measurements of the nonlinear conductance of quantum point contacts

B. Naser, D. K. Ferry, J. Heeren, J. L. Reno, and J. P. Bird

Appl. Phys. Lett. 90, 043103 (2007); http://dx.doi.org/10.1063/1.2433038 (3 pages) | Cited 4 times

Online Publication Date: 22 January 2007

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The conductance of quantum point contacts (QPCs) subject to strongly nonlinear source-drain biasing is investigated with transient pulses. The authors investigations reveal the presence of a characteristic fixed point, at which the transient conductance (Gt) is bias independent. This point corresponds to the situation where the unbiased QPC is almost depopulated and can apparently be accounted for by considering the unidirectional population of QPC subbands by the transient voltage. To discuss the variations of Gt away from the fixed point, it is necessary to consider the influence of the applied bias on the QPC profile and electron-phonon scattering.
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73.63.Rt Nanoscale contacts
71.38.-k Polarons and electron-phonon interactions
63.20.K- Phonon interactions

Diameter dependent transport properties of gallium nitride nanowire field effect transistors

Abhishek Motayed, Mark Vaudin, Albert V. Davydov, John Melngailis, Maoqi He, and S. N. Mohammad

Appl. Phys. Lett. 90, 043104 (2007); http://dx.doi.org/10.1063/1.2434153 (3 pages) | Cited 34 times

Online Publication Date: 22 January 2007

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The authors report transport property measurements of individual GaN nanowire field effect transistors and the correlation of the electron mobilities with the existence of grain boundaries in these nanowires. Room temperature field effect electron mobilities as high as 319 cm2 V−1 s−1 were obtained for the 200 nm diameter nanowires. Mobilities calculated from these reliable nanowire field effect transistors indicated that the surface scattering plays a dominant role in smaller diameter nanowires, whereas for intermediate diameter devices transport is dominated by grain boundary scattering. Reduction of the mobility with decreasing diameter of nanowires can be explained using “continuous surface” model.
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85.30.Tv Field effect devices
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
85.30.De Semiconductor-device characterization, design, and modeling

Bending strength and flexibility of ZnO nanowires

C. Q. Chen and J. Zhu

Appl. Phys. Lett. 90, 043105 (2007); http://dx.doi.org/10.1063/1.2432289 (3 pages) | Cited 24 times

Online Publication Date: 22 January 2007

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The fracture strain, strength, and flexibility of ZnO nanowires (NWs) with a large range of diameters (85–542 nm) are investigated at a quantitative level. Large strains up to 4%–7% have been obtained before the final elastic fracture, corresponding to fracture strengths close to the theoretical strength. The flexibility of a NW is discussed quantitatively in terms of the diameter and fracture strain. The fundamental mechanisms responsible for the observed exceptional properties are discussed.
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81.05.Dz II-VI semiconductors
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.40.Lm Deformation, plasticity, and creep
62.20.M- Structural failure of materials
62.20.F- Deformation and plasticity

Young’s modulus reduction of defective nanotubes

Nicola M. Pugno

Appl. Phys. Lett. 90, 043106 (2007); http://dx.doi.org/10.1063/1.2425048 (3 pages) | Cited 11 times

Online Publication Date: 22 January 2007

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In this letter the author calculate, by applying fracture mechanics, Young’s modulus reduction for a nanotube, imposed by the presence of nanodefects, with specified size, shape, and number. The results are compared with atomistic and continuum simulations. Vacancy fraction, eccentricity, orientation, and interaction of defects are found to be the key parameters influencing the stiffness degradation.
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62.25.-g Mechanical properties of nanoscale systems
61.46.Fg Nanotubes
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials

Thermopower profiling of a silicon p-n junction

Kyeongtae Kim, Jisang Park, Sun Ung Kim, Ohmyoung Kwon, Joon Sik Lee, Seungho Ho Park, and Young Ki Choi

Appl. Phys. Lett. 90, 043107 (2007); http://dx.doi.org/10.1063/1.2432949 (3 pages) | Cited 4 times

Online Publication Date: 23 January 2007

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An ac type thermopower measurement technique was suggested and demonstrated with a simple experimental setup. The thermopower distribution across a silicon p-n junction was measured point by point at every 10 nm, so that it was free from the noise due to the built-in potential and photoionization effects, and it was compared with the theoretical result. Although this ac type thermopower measurement technique could not follow the sharp variation of the theoretical thermopower near the p-n junction, it could identify a smooth peak of the thermopower distribution in the depletion layer of the p-n junction.
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73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.Pa Thermoelectric and thermomagnetic effects

Size control of catalytic nanoparticles by thermal treatment and its application to diameter control of single-walled carbon nanotubes

Goo-Hwan Jeong, Satoru Suzuki, Yoshihiro Kobayashi, Akira Yamazaki, Hideyuki Yoshimura, and Yoshikazu Homma

Appl. Phys. Lett. 90, 043108 (2007); http://dx.doi.org/10.1063/1.2433024 (3 pages) | Cited 17 times

Online Publication Date: 23 January 2007

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The authors report size control of catalytic nanoparticles by thermal annealing for diameter-controlled growth of single-walled carbon nanotubes (SWNTs). They found that Co nanoparticle-size gradually decreased through repetitive annealing at 1000 °C in Ar ambient. Results of x-ray photoelectron spectroscopy and secondary ion mass spectroscopy show that thermal evaporation is responsible for the decrease. After SWNT growth using this phenomenon, the authors found that thinner SWNTs with a narrower diameter distribution grew as the nanoparticles became smaller. Their results provide a rational and straightforward technique to prepare catalysts having a desirable size and uniformity toward diameter-controlled SWNT growth.
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81.07.De Nanotubes
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
81.40.Gh Other heat and thermomechanical treatments
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Multiplexing single electron transistors for application in scalable solid-state quantum computing

Vincent I. Conrad, Andrew D. Greentree, and Lloyd C. L. Hollenberg

Appl. Phys. Lett. 90, 043109 (2007); http://dx.doi.org/10.1063/1.2435335 (3 pages) | Cited 2 times

Online Publication Date: 23 January 2007

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Single electron transistors (SETs) are nanoscale electrometers of unprecedented sensitivity, and as such have been proposed as readout devices in a number of quantum computer architectures. The authors show that the functionality of a standard SET can be multiplexed so as to operate as both readout device and control gate for solid-state qubit systems based on charge localization and spin-charge transduction. Such multiplexing offers new possibilities for gate density reduction in nanoscale devices, and may therefore play a role in scalable quantum computer architectures.
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85.35.Gv Single electron devices

Optical properties of PbSe nanocrystal quantum dots under pressure

Kirill K. Zhuravlev, Jeffrey M. Pietryga, Robert K. Sander, and Richard D. Schaller

Appl. Phys. Lett. 90, 043110 (2007); http://dx.doi.org/10.1063/1.2431777 (3 pages) | Cited 7 times

Online Publication Date: 24 January 2007

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The optical properties of PbSe nanocrystal quantum dots (NQDs) were studied as a function of applied hydrostatic pressure over the range from ambient to 5.4 GPa. PbSe NQDs exhibit an energy gap that is dominated by quantum confinement. Despite such strong confinement, the authors find that the energy gaps of 3, 5, and 7 nm diameter PbSe NQDs change monotonically with pressure with a dependence that is almost entirely determined by the bulk deformation potential. The sizable dependence of the NQD energy gap with pressure invites applications in the areas of high speed pressure sensing and tunable IR lasers.
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78.67.Hc Quantum dots
73.21.La Quantum dots
62.50.-p High-pressure effects in solids and liquids

Ni–NiO core-shell nanoclusters with cubic shape by nanocluster beam deposition

Y. Z. Zhou, J. S. Chen, B. K. Tay, J. F. Hu, G. M. Chow, T. Liu, and P. Yang

Appl. Phys. Lett. 90, 043111 (2007); http://dx.doi.org/10.1063/1.2434165 (3 pages) | Cited 15 times

Online Publication Date: 24 January 2007

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Ni nanoclusters with cubic shape and uniform size below 10 nm were fabricated by nanocluster beam deposition. Ni–NiO core-shell structure was achieved when the Ni clusters flew through a chamber with constant oxygen feeding (1–3 SCCM, SCCM denotes cubic centimeter per minute at STP). The fraction of oxidized Ni was estimated by means of linear combination fitting to the x-ray absorption near-edge structure data. The hysteresis loop of the oxidized sample (1 SCCM O2) showed a shift of ∼ 181 Oe with 100 Oe field cooling from 400 K and a coercivity of 48 Oe at room temperature, while the nonoxidized Ni nanoclusters with size of 4–5 nm showed superparamagnetic behavior.
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61.46.Bc Structure of clusters (e.g., metcars; not fragments of crystals; free or loosely aggregated or loosely attached to a substrate)
78.70.Dm X-ray absorption spectra
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Tt Fine-particle systems; nanocrystalline materials
81.07.Bc Nanocrystalline materials

Comparative studies of compressibility between nanocrystalline and bulk nickel

Jianzhong Zhang, Yusheng Zhao, and Bogdan Palosz

Appl. Phys. Lett. 90, 043112 (2007); http://dx.doi.org/10.1063/1.2435325 (3 pages) | Cited 19 times

Online Publication Date: 24 January 2007

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The authors conducted a comparative study of compressibility between nanocrystalline and bulk nickel using synchrotron x-ray diffraction at pressures up to 7.4 GPa. Their results present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. It is also observed that the bulk moduli determined using the apparent lattice parameters are 17%–18% lower at the smaller diffraction vectors (Q = 2π/d) than those at the larger Q values. These findings support the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer.
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81.40.Lm Deformation, plasticity, and creep
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.F- Deformation and plasticity
62.20.D- Elasticity
61.46.Hk Nanocrystals
61.66.Bi Elemental solids

High Q factor for mechanical resonances of batch-fabricated SiC nanowires

S. Perisanu, P. Vincent, A. Ayari, M. Choueib, S. T. Purcell, M. Bechelany, and D. Cornu

Appl. Phys. Lett. 90, 043113 (2007); http://dx.doi.org/10.1063/1.2432257 (3 pages) | Cited 23 times

Online Publication Date: 24 January 2007

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The authors present here the measurements of high mechanical Q factors for singly clamped, batch-fabricated SiC nanowires measured by field emission (FE) in ultrahigh vacuum. The resonances of two nanowires, glued to the ends of tungsten support tips, were electrostatically excited and detected by the variation in the FE microscopy (FEM) images. Low amplitude oscillations were measured by numerical analysis of the FEM image blurring during frequency scans through the resonances. This avoided the artificial broadening of the resonances by nonlinear effects. A room temperature Q factor of 159 000 was achieved after high temperature in situ cleaning.
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85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
07.10.Cm Micromechanical devices and systems

Combined scanning force microscopy and scanning tunneling spectroscopy of an electronic nanocircuit at very low temperature

J. Senzier, P. S. Luo, and H. Courtois

Appl. Phys. Lett. 90, 043114 (2007); http://dx.doi.org/10.1063/1.2436651 (3 pages) | Cited 10 times

Online Publication Date: 25 January 2007

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The authors demonstrate the combination of scanning force microscopy and scanning tunneling spectroscopy in a local probe microscope operating at very low temperature (60 mK). This local probe uses a quartz tuning fork ensuring high tunnel junction stability. They performed the spatially resolved spectroscopic study of a superconducting nanocircuit patterned on an insulating substrate. Significant deviations from the theoretical prediction are observed.
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85.25.Am Superconducting device characterization, design, and modeling

Critical diameter for III-V nanowires grown on lattice-mismatched substrates

Linus C. Chuang, Michael Moewe, Chris Chase, Nobuhiko P. Kobayashi, Connie Chang-Hasnain, and Shanna Crankshaw

Appl. Phys. Lett. 90, 043115 (2007); http://dx.doi.org/10.1063/1.2436655 (3 pages) | Cited 60 times

Online Publication Date: 25 January 2007

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The authors report the experimental observation of a critical diameter (CD) of III-V compound semiconductor epitaxial nanowires (NWs) grown on lattice-mismatched substrates using Au-catalyzed vapor-liquid-solid growth. The CD is found to be inversely proportional to the lattice mismatch. NWs with well-aligned orientation are synthesized with catalysts smaller than the CD. Well-aligned InP NWs grown on a Si substrate exhibit a record low photoluminescence linewidth (5.1 meV) and a large blueshift (173 meV) from the InP band gap energy due to quantization. Well-aligned InAs NWs grown on a Si substrate are also demonstrated.
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81.05.Ea III-V semiconductors
81.07.Bc Nanocrystalline materials
78.55.Cr III-V semiconductors
81.16.-c Methods of micro- and nanofabrication and processing
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
61.46.Hk Nanocrystals

Capacitance measurements on small parallel plate capacitors using nanoscale impedance microscopy

Olivier Schneegans, Pascal Chrétien, Frédéric Houzé, and René Meyer

Appl. Phys. Lett. 90, 043116 (2007); http://dx.doi.org/10.1063/1.2437052 (3 pages) | Cited 5 times

Online Publication Date: 25 January 2007

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Capacitance values in the picofarad to femtofarad range have been measured on a set of square parallel plate capacitors using a homemade nanoscale impedance microscopy (NIM) device and compared with numerical simulations. A simple analytical model involving the main geometrical parameters is proposed, which correctly fits the experimental results. This model was validated by further measurements on rectangular electrodes and capacitors surrounded by guard rings. The edge effects and stray capacitance contribution were hence determined. Finally, the present resolution of our NIM device was estimated by imaging a tiny 8×8 μm2 capacitor, confirming the relevance of such reference samples.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
84.32.Tt Capacitors
06.20.fb Standards and calibration

Photovoltaic enhancement of organic solar cells by a bridged donor-acceptor block copolymer approach

Sam-Shajing Sun, Cheng Zhang, Abram Ledbetter, Soobum Choi, Kang Seo, Carl E. Bonner, Jr., Martin Drees, and Niyazi Serdar Sariciftci

Appl. Phys. Lett. 90, 043117 (2007); http://dx.doi.org/10.1063/1.2437100 (3 pages) | Cited 37 times

Online Publication Date: 25 January 2007

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The authors show that a photovoltaic device composed of a -donor-bridge–acceptor-bridge- type block copolymer thin film exhibits a significant performance improvement over its corresponding donor/acceptor blend (Voc increased from 0.14 to 1.10 V and Jsc increased from 0.017 to 0.058 mA/cm2) under identical conditions, where donor is an alkyl derivatized poly-p-phenylenevinylene (PPV) conjugated block, acceptor is a sulfone-alkyl derivatized PPV conjugated block, and bridge is a nonconjugated and flexible unit. The authors attribute such improvement to the block copolymer intrinsic nanophase separation and molecular self-assembly that results in the reduction of the exciton and carrier losses.
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84.60.Jt Photoelectric conversion
85.30.-z Semiconductor devices
72.40.+w Photoconduction and photovoltaic effects
71.35.-y Excitons and related phenomena
64.75.-g Phase equilibria

Large area 50 nm period grating by multiple nanoimprint lithography and spatial frequency doubling

Bo Cui, Zhaoning Yu, Haixiong Ge, and Stephen Y. Chou

Appl. Phys. Lett. 90, 043118 (2007); http://dx.doi.org/10.1063/1.2390652 (3 pages) | Cited 7 times

Online Publication Date: 25 January 2007

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The authors have developed an approach to fabricate large area 50 nm period gratings (22 nm linewidth) with low cost. The method used a fabrication cycle twice, each combining nanoimprint lithography with a spatial frequency doubling based on electroless plating, lift-off, and reactive ion etching. Hence by frequency doubling twice, we started with a 200 nm period grating mold and finished with a 50 nm period grating with a uniform area of 3 cm2—the largest achieved today. This method is scalable for the fabrication of even smaller period gratings over a large area, and is a viable low-cost technique for making nanoimprint lithography molds for high-throughput fabrication of 50 nm period grating or grid devices.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
81.16.Nd Micro- and nanolithography
42.79.Dj Gratings

One by one control of the exact number of carbon nanotubes formed by chemical vapor deposition growth: A digital growth process

Masatoshi Maeda, Takafumi Kamimura, and Kazuhiko Matsumoto

Appl. Phys. Lett. 90, 043119 (2007); http://dx.doi.org/10.1063/1.2432227 (3 pages) | Cited 2 times

Online Publication Date: 26 January 2007

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The authors have succeeded in precisely controlling the exact number of individual bridging carbon nanotubes (CNTs) between two electrodes during thermal chemical vapor deposition (CVD) by counting the number of steps in a monitoring current. A direct current bias was applied between electrodes and the resulting current was monitored during the CVD process. The monitoring current showed several steplike increases, each of which corresponded to bridging by a single CNT. After thermal CVD, the number of bridging CNTs was confirmed by scanning electron microscopy observation and by the electrical breakdown process: the results coincided exactly with the number of current steps monitored during the CVD growth.
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61.46.Fg Nanotubes
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
73.63.Fg Nanotubes
77.22.Jp Dielectric breakdown and space-charge effects

Hydrophilic polymer assisted synthesis of room-temperature ferromagnetic Fe3O4 nanochains

B. Y. Geng, J. Z. Ma, X. W. Liu, Q. B. Du, M. G. Kong, and L. D. Zhang

Appl. Phys. Lett. 90, 043120 (2007); http://dx.doi.org/10.1063/1.2432248 (3 pages) | Cited 15 times

Online Publication Date: 26 January 2007

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One-dimensional chains consisting of crystalline Fe3O4 nanoparticles have been synthesized by using a polyacrylic acid template method. The characterizations of composition, structure, and magnetic property of the chains are performed. The formation mechanism of Fe3O4 nanocrystal chains is proposed to be a polymer template and magnetostatic interaction. In a weak magnetic field, the synthesized nanochains can be reorganized. The as-synthesized nanochains are ferromagnetic at room temperature with lower saturation magnetization and higher coercivity value than those of bulk Fe3O4, which could have potential applications in nanosensors for rapid and sensitive detection of biologic or chemical molecules.
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81.16.Be Chemical synthesis methods
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Vv High coercivity materials

Room temperature ferromagnetism in Mn+-implanted Si nanowires

H. W. Wu, C. J. Tsai, and L. J. Chen

Appl. Phys. Lett. 90, 043121 (2007); http://dx.doi.org/10.1063/1.2432273 (3 pages) | Cited 28 times

Online Publication Date: 26 January 2007

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Room temperature ferromagnetism of Mn+-implanted Si nanowires (NWs) has been discovered. The saturation magnetization was found to increase with the Mn concentration. Healing the damages in crystallinity at 600 °C led to an increase in magnetization, while the ferromagnetism disappeared upon annealing at 800 °C as Mn atoms segregated to the surface of NWs. The results indicate that Mn+-implanted Si NWs are potentially useful for nanoscale spintronics applications.
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75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Pp Magnetic semiconductors
75.50.Gg Ferrimagnetics

Anchoring gold nanoparticles onto a mica surface by oxygen plasma ashing for sequential nanocomponent assembly

Akihiko Takagi, Kaoru Ojima, Eriko Mikamo, Takuya Matsumoto, and Tomoji Kawai

Appl. Phys. Lett. 90, 043122 (2007); http://dx.doi.org/10.1063/1.2432276 (3 pages) | Cited 2 times

Online Publication Date: 26 January 2007

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Water-soluble gold nanoparticles were immobilized in both polar (water) and nonpolar (chloroform) liquids on hydrophilic mica surface by oxygen plasma ashing. It is then demonstrated that a DNA with a thiol at an extremity is attached to the immobilized nanoparticles due to the gold-thiol coupling and stretched in the flow direction of the following water rinse. This technique allows a sequential integration of nanoparticles and molecules for various solutions, since the nanoparticles remain on a solid surface rather than dissolve into the solution.
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81.65.Cf Surface cleaning, etching, patterning
52.77.Bn Etching and cleaning
87.14.G- Nucleic acids
87.15.-v Biomolecules: structure and physical properties

Plastic deformation of gallium arsenide micropillars under uniaxial compression at room temperature

Johann Michler, Kilian Wasmer, Stephan Meier, Fredrik Östlund, and Klaus Leifer

Appl. Phys. Lett. 90, 043123 (2007); http://dx.doi.org/10.1063/1.2432277 (3 pages) | Cited 31 times

Online Publication Date: 26 January 2007

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The authors have experimentally investigated the compressive strength of GaAs pillars with a diameter of 1 μm by uniaxial compression tests. The tests were performed at room temperature and, contrary to macroscopic tests, the micropillars were found to exhibit ductile plasticity comparable to that of metal single crystal micropillars. The yield stress was 1.8±0.4 GPa and, for one pillar that was more closely examined, a total deformation of 24% was observed. In the diffraction patterns from transmission electron microscopy studies of this pillar, a high density of twins was observed.
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81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
61.72.Mm Grain and twin boundaries
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