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26 Dec 2011

Volume 99, Issue 26, Articles (26xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 99, 261101 (2011); http://dx.doi.org/10.1063/1.3660243 (3 pages)

T. Schwarzbäck, H. Kahle, M. Eichfelder, R. Roßbach, M. Jetter, and P. Michler
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Optical properties of a-plane (Al, Ga)N/GaN multiple quantum wells grown on strain engineered Zn1−xMgxO layers by molecular beam epitaxy

Y. Xia, J. Brault, M. Nemoz, M. Teisseire, B. Vinter, M. Leroux, and J.-M. Chauveau

Appl. Phys. Lett. 99, 261910 (2011); http://dx.doi.org/10.1063/1.3673325 (3 pages)

Online Publication Date: 29 December 2011

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Nonpolar (11math0) Al0.2Ga0.8N/GaN multiple quantum wells (MQWs) have been grown by molecular beam epitaxy on (11math0) Zn0.74Mg0.26O templates on r-plane sapphire substrates. The quantum wells exhibit well-resolved photoluminescence peaks in the ultra-violet region, and no sign of quantum confined Stark effect is observed in the complete multiple quantum well series. The results agree well with flat band quantum well calculations. Furthermore, we show that the MQW structures are strongly polarized along the [0001] direction. The origin of the polarization is discussed in terms of the strain anisotropy dependence of the exciton optical oscillator strengths.
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78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
71.35.-y Excitons and related phenomena
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Cr III-V semiconductors

Quantitative strain mapping of InAs/InP quantum dots with 1 nm spatial resolution using dark field electron holography

David Cooper, Jean-Luc Rouviere, Armand Béché, Shima Kadkhodazadeh, Elizaveta S. Semenova, Kresten Yvind, and Rafal Dunin-Borkowski

Appl. Phys. Lett. 99, 261911 (2011); http://dx.doi.org/10.1063/1.3672194 (3 pages) | Cited 5 times

Online Publication Date: 30 December 2011

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The optical properties of semiconductor quantum dots are greatly influenced by their strain state. Dark field electron holography has been used to measure the strain in InAs quantum dots grown in InP with a spatial resolution of 1 nm. A strain value of 5.4% ± 0.1% has been determined which is consistent with both measurements made by geometrical phase analysis of high angle annular dark field scanning transmission electron microscopy images and with simulations.
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78.67.Hc Quantum dots
68.65.Hb Quantum dots (patterned in quantum wells)
61.05.jp Electron holography

Thermal expansion coefficients of Bi2Se3 and Sb2Te3 crystals from 10 K to 270 K

X. Chen, H. D. Zhou, A. Kiswandhi, I. Miotkowski, Y. P. Chen, P. A. Sharma, A. L. Lima Sharma, M. A. Hekmaty, D. Smirnov, and Z. Jiang

Appl. Phys. Lett. 99, 261912 (2011); http://dx.doi.org/10.1063/1.3672198 (3 pages) | Cited 6 times

Online Publication Date: 30 December 2011

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Lattice constant of Bi2Se3 and Sb2Te3 crystals is determined by x-ray powder diffraction measurement in a wide temperature range. Linear thermal expansion coefficients (α) of the crystals are extracted, and considerable anisotropy between α|| and α⊥ is observed. The low temperature values of α can be fit well by the Debye model, while an anomalous behavior at above 150 K is evidenced and explained. Grüneisen parameters of the materials are also estimated at room temperature.
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65.40.De Thermal expansion; thermomechanical effects
61.66.Fn Inorganic compounds

Interplay of index contrast with periodicity in polymer photonic crystals

Chris E. Finlayson, Andrew I. Haines, David R. E. Snoswell, Andreas Kontogeorgos, Silvia Vignolini, Jeremy J. Baumberg, Peter Spahn, and G. Peter Hellmann

Appl. Phys. Lett. 99, 261913 (2011); http://dx.doi.org/10.1063/1.3672215 (4 pages) | Cited 3 times

Online Publication Date: 30 December 2011

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We report how the strength of resonant Bragg reflection from polymeric photonic crystals (polymer opals) varies linearly with the refractive-index contrast, Δn, in contrast to the quadratic buildup of Fresnel reflections scaling as (Δn)2. This occurs due to the interplay of disorder and periodicity, in agreement with a simple 1-dimensional periodic model. Goniometry experiments show that opal films exhibit “cones” of resonantly scattered light, which extend to ±20° angular deviation from the specular direction. The intensity of the scattering cones varies super-linearly with Δn. Such medium contrast photonic crystals are of significant interest for understanding structural colors exhibited in nature, by structures with inherent disorder.
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42.70.Qs Photonic bandgap materials
42.70.Jk Polymers and organics

Influence of silicon on the thermally-induced crystallization process of Si-Sb4Te phase change materials

Yan Cheng, Zhitang Song, Yifeng Gu, Sannian Song, Feng Rao, Liangcai Wu, Bo Liu, and Songlin Feng

Appl. Phys. Lett. 99, 261914 (2011); http://dx.doi.org/10.1063/1.3673281 (4 pages)

Online Publication Date: 30 December 2011

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Si-Sb4Te phase change thin films with different silicon contents have been investigated by in situ heating technique in transmission electron microscopy (TEM). The studies show that Si-doping can significantly improve the thermal stability of Si-Sb4Te thin films, refine their grain size, and change the nucleation characters with the increase of silicon content. By in situ annealing in TEM, the crystalline phase of Si-Sb4Te thin films can be indexed as hexagonal Sb structure, and Si is still holding amorphous state which is considered as the reason for the change, by destroying the long-range order lattice of crystal grains.
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61.72.up Other materials
68.55.at Other materials
64.70.dg Crystallization of specific substances
81.40.Gh Other heat and thermomechanical treatments
64.60.qj Studies of nucleation in specific substances
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Distribution of electronic reconstruction at the n-type LaAlO3/SrTiO3 interface revealed by hard x-ray photoemission spectroscopy

Y. Y. Chu, Y. F. Liao, V. T. Tra, J. C. Yang, W. Z. Liu, Y. H. Chu, J. Y. Lin, J. H. Huang, J. Weinen, S. Agrestini, K.-D. Tsuei, and D. J. Huang

Appl. Phys. Lett. 99, 262101 (2011); http://dx.doi.org/10.1063/1.3672099 (3 pages) | Cited 1 time

Online Publication Date: 27 December 2011

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We investigated the electronic reconstruction at the n-type LaAlO3/SrTiO3 interface with hard x-ray photoelectron spectroscopy (HAXPES) under grazing incidence. By exploiting the collapse of evanescent x-ray waves and the abrupt increase of x-ray absorption at the critical incidence angle, our HAXPES study reveals a 2% electronic reconstruction from Ti4+ to Ti3+ occurring near the interface. Such an electronic reconstruction also extends from the interface into SrTiO3 with a depth of about 48 Å (∼12 unit cells) and an estimated total charge transfer of ∼0.24 electrons per two-dimensional unit cell.
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79.60.Bm Clean metal, semiconductor, and insulator surfaces
78.70.Dm X-ray absorption spectra

Enhancement of the photoelectrochemical properties of Cl-doped ZnO nanowires by tuning their coaxial doping profile

Jiandong Fan, Frank Güell, Cristian Fábrega, Alexey Shavel, Alex Carrete, Teresa Andreu, Joan Ramón Morante, and Andreu Cabot

Appl. Phys. Lett. 99, 262102 (2011); http://dx.doi.org/10.1063/1.3673287 (4 pages) | Cited 5 times

Online Publication Date: 27 December 2011

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Arrays of vertically aligned ZnO:Cl/ZnO core-shell nanowires were used to demonstrate that the control of the coaxial doping profile in homojunction nanostructures can improve their surface charge carrier transfer while conserving potentially excellent transport properties. It is experimentally shown that the presence of a ZnO shell enhances the photoelectrochemical properties of ZnO:Cl nanowires up to a factor 5. Likewise, the ZnO shell promotes the visible photoluminescence band in highly conducting ZnO:Cl nanowires. These lines of evidence are associated with the increase of the nanowires’ surface depletion layer.
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61.72.uj III-V and II-VI semiconductors
82.50.-m Photochemistry
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
78.40.Fy Semiconductors
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors

Origin of charge separation in III-nitride nanowires under strain

Yelong Wu, Guangde Chen, Su-Huai Wei, Mowafak M. Al-Jassim, and Yanfa Yan

Appl. Phys. Lett. 99, 262103 (2011); http://dx.doi.org/10.1063/1.3673323 (3 pages) | Cited 1 time

Online Publication Date: 28 December 2011

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The structural and electronic properties of BN, AlN, and GaN nanowires (NWs) under different strain condition are investigated using first-principles calculations. We found an anomaly of band gap change with respect to the applied external uniaxial strain. We show that this is due to the band crossing caused by the crystal field splitting at the top of the valance band. Due to the difference of the atomic relaxation at the core and surface regions of the NW, we show that electron and hole separation can be achieved when the compressive uniaxial strain exceeds the critical value |εc|.
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61.46.Km Structure of nanowires and nanorods (long, free or loosely attached, quantum wires and quantum rods, but not gate-isolated embedded quantum wires)
71.20.Nr Semiconductor compounds
71.70.Ch Crystal and ligand fields

GaSb nanowire single-hole transistor

Bahram Ganjipour, Henrik A. Nilsson, B. Mattias Borg, Lars-Erik Wernersson, Lars Samuelson, H. Q. Xu, and Claes Thelander

Appl. Phys. Lett. 99, 262104 (2011); http://dx.doi.org/10.1063/1.3673328 (3 pages) | Cited 3 times

Online Publication Date: 28 December 2011

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We present an experimental study of single hole transistors (SHTs) made from p-type GaSb nanowires. Closely spaced source-drain electrodes are fabricated onto GaSb nanowires to define a SHT within a GaSb nanowire. Room temperature back-gate transfer characteristics show typical hole transport behavior. The fabricated devices are characterized by transport measurements at 1.5 K, where periodic conductance oscillations due to Coulomb blockade are observed and a charging energy of 5 meV is determined.
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85.35.Ds Quantum interference devices

Determination of secondary phases in kesterite Cu2ZnSnS4 thin films by x-ray absorption near edge structure analysis

Justus Just, Dirk Lützenkirchen-Hecht, Ronald Frahm, Susan Schorr, and Thomas Unold

Appl. Phys. Lett. 99, 262105 (2011); http://dx.doi.org/10.1063/1.3671994 (3 pages) | Cited 6 times

Online Publication Date: 29 December 2011

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Secondary phases in Cu2ZnSnS4 (CZTS) are investigated by x-ray absorption spectroscopy. Evaluating the x-ray absorption near edge structure at the sulfur K-edge, we show that secondary phases exhibit sufficiently distinct features to allow their quantitative determination with high accuracy. We are able to quantify the ZnS fraction with an absolute accuracy of ±3%, by applying linear combination analysis using reference spectra. We find that even in CZTS thin films with [Sn]/[Zn] ≈ 1, a significant amount of ZnS can be present. A strong correlation of the ZnS-content with the degradation of the electrical performance of solar cells is observed.
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88.40.jn Thin film Cu-based I-III-VI2 solar cells
78.70.Dm X-ray absorption spectra

Electron mobility limited by scattering from screened positively charged dislocation lines within indium nitride

Erfan Baghani and Stephen K. O’Leary

Appl. Phys. Lett. 99, 262106 (2011); http://dx.doi.org/10.1063/1.3671117 (3 pages) | Cited 4 times

Online Publication Date: 30 December 2011

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In the present work, we address the open question of the contribution from threading dislocations to the problem of unintentional n-type conductivity exhibited by indium nitride through an examination of the effect that positively charged dislocation lines have on the transverse electron mobility within this material. Assuming that the threading dislocation lines within indium nitride act as a source for free electrons, the screening associated with the positively charged threading dislocation lines is evaluated. The impact this screening has on the dislocation limited electron mobility within this material is then considered. Our results indicate that one of the implications of attributing a donor character to the threading dislocation lines within indium nitride would be a strong non-uniformity in the free electron concentration in the plane of growth of this semiconductor. This contrasts dramatically with the case of gallium nitride.
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72.80.Ey III-V and II-VI semiconductors
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
72.20.Ee Mobility edges; hopping transport
72.20.Fr Low-field transport and mobility; piezoresistance
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Tuning the surface magnetism of γ-Fe2O3 nanoparticles with a Cu shell

R. D. Desautels, E. Skoropata, Y.-Y. Chen, H. Ouyang, J. W. Freeland, and J. van Lierop

Appl. Phys. Lett. 99, 262501 (2011); http://dx.doi.org/10.1063/1.3671989 (4 pages) | Cited 3 times

Online Publication Date: 27 December 2011

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An interfacial monolayer of CuO in Cu-coated γ-Fe2O3 nanoparticles enables significantly decreased intrinsic surface spin disorder compared to bare γ-Fe2O3 nanoparticles. Element specific x-ray absorption spectroscopy at the L-edges for Cu and Fe indicates that the magnetic moment of the CuO in the shell interacts with the γ-Fe2O3 nanoparticle’s surface magnetic moments. This exchange interaction cants the moments of the CuO resulting in a non-zero Cu moment, altering the γ-Fe2O3 nanomagnetism.
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75.70.Rf Surface magnetism
75.50.Tt Fine-particle systems; nanocrystalline materials
78.70.Dm X-ray absorption spectra
75.30.Cr Saturation moments and magnetic susceptibilities

Coherence in a transmon qubit with epitaxial tunnel junctions

Martin P. Weides, Jeffrey S. Kline, Michael R. Vissers, Martin O. Sandberg, David S. Wisbey, Blake R. Johnson, Thomas A. Ohki, and David P. Pappas

Appl. Phys. Lett. 99, 262502 (2011); http://dx.doi.org/10.1063/1.3672000 (3 pages) | Cited 6 times

Online Publication Date: 27 December 2011

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We developed transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T1 is 0.72−0.86 μs and the ensemble dephasing time T2* is slightly larger than T1. The dephasing time T2 (1.36 μs) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit’s inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements.
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84.32.Tt Capacitors

Fast switching of magnetization in the ferromagnetic semiconductor (Ga,Mn)(As,P) using nonequilibrium phonon pulses

A. Casiraghi, P. Walker, A. V. Akimov, K. W. Edmonds, A. W. Rushforth, E. De Ranieri, R. P. Campion, B. L. Gallagher, and A. J. Kent

Appl. Phys. Lett. 99, 262503 (2011); http://dx.doi.org/10.1063/1.3672029 (3 pages) | Cited 1 time

Online Publication Date: 28 December 2011

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We use short acoustic pulses to induce a fast irreversible switching of the magnetization orientation in a layer of (Ga,Mn)(As,P). The pulses are generated by femtosecond optical excitation of a metal transducer film and travel ballistically through the sample. We show that the switching is triggered by incoherent acoustic phonons, occurs through domain-related processes, and is concluded in ∼35 ns. We suggest that the mechanism behind the switching involves the holes in the material being heated due to their coupling to the phonons.
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75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
75.30.Gw Magnetic anisotropy

Magnon magnetoresistance of NiFe nanowires: Size dependence and domain wall detection

V. D. Nguyen, C. Naylor, L. Vila, A. Marty, P. Laczkowski, C. Beigné, L. Notin, Z. Ishaque, and J. P. Attané

Appl. Phys. Lett. 99, 262504 (2011); http://dx.doi.org/10.1063/1.3672828 (3 pages) | Cited 3 times

Online Publication Date: 28 December 2011

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The magnetoresistance of permalloy (Ni84Fe16) nanowires of various widths (down to 50 nm) has been measured for fields applied along the wires. The enhancement of the shape anisotropy in the narrowest widths leads to the disappearance of the anisotropic magnetoresistance signal, the remaining contribution to the magnetoresistance being that of the magnons. Using constrictions to pin a domain wall, we show that the magnon magnetoresistance signal can give access to the position of the domain wall along the wire.
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72.15.Gd Galvanomagnetic and other magnetotransport effects
75.30.Ds Spin waves
75.60.Ch Domain walls and domain structure
75.30.Gw Magnetic anisotropy
75.75.-c Magnetic properties of nanostructures

All-electrical operation of magnetic vortex core memory cell

K. Nakano, D. Chiba, N. Ohshima, S. Kasai, T. Sato, Y. Nakatani, K. Sekiguchi, K. Kobayashi, and T. Ono

Appl. Phys. Lett. 99, 262505 (2011); http://dx.doi.org/10.1063/1.3673303 (3 pages) | Cited 8 times

Online Publication Date: 29 December 2011

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A single vortex-core switching in a ferromagnetic disk is detected in real time by using a three-terminal device with the tunneling magnetoresistance junction. We show that the device works as a vortex core memory cell, where reading and writing can be done in an all-electrical way: binary data corresponding to the core direction can be read out electrically as the amplitude of the output, while the data can be written electrically by applying a pulsed current.
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85.70.-w Magnetic devices

Spin-transfer mechanism for magnon-drag thermopower

M. E. Lucassen, C. H. Wong, R. A. Duine, and Y. Tserkovnyak

Appl. Phys. Lett. 99, 262506 (2011); http://dx.doi.org/10.1063/1.3672207 (3 pages) | Cited 1 time

Online Publication Date: 30 December 2011

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We point out a relation between the dissipative spin-transfer-torque parameter β and the contribution of magnon drag to the thermoelectric power in conducting ferromagnets. Using this result, we estimate β in iron at low temperatures, where magnon drag is believed to be the dominant contribution to the thermopower. Our results may be used to determine β from magnon-drag-thermopower experiments, or, conversely, to infer the strength of magnon drag via experiments on spin transfer.
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72.25.-b Spin polarized transport
75.30.Ds Spin waves
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
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Comparative study on aging effect in BiFeO3 thin films substituted at A- and B-sites

Xi Wang, Guangda Hu, Ling Cheng, Changhong Yang, and Weibing Wu

Appl. Phys. Lett. 99, 262901 (2011); http://dx.doi.org/10.1063/1.3672212 (3 pages) | Cited 4 times

Online Publication Date: 27 December 2011

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Typical characteristics of aging effect, double hysteresis loops, were observed in (100)pseudocubic-oriented Bi0.95Ca0.05FeO3 (BCFO) and BiFe0.95Ni0.05O3 (BFNO) films grown on LaNiO3(100)/Si substrates. The double hysteresis loops for BCFO film become less “constrained” with increasing applied voltage compared to that for BFNO, indicating that the aging effect is more severe in the latter. This can be demonstrated by the lower leakage current and smaller dielectric constant for BFNO. These phenomena are explained based on the crystal structure and defect chemistry.
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77.55.fp Other ferroelectric films
81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging
77.22.Ch Permittivity (dielectric function)
77.80.Dj Domain structure; hysteresis
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Trap-state whispering-gallery mode lasing from high-quality tin-doped CdS whiskers

R. B. Liu, X. J. Zhuang, J. Y. Xu, D. B. Li, Q. L. Zhang, K. Ding, P. B. He, C. Z. Ning, B. S. Zou, and A. L. Pan

Appl. Phys. Lett. 99, 263101 (2011); http://dx.doi.org/10.1063/1.3672032 (4 pages) | Cited 3 times

Online Publication Date: 27 December 2011

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High-quality surface tin-doped hexagonal CdS whiskers were synthesized by a well-controlled in situ source exchange chemical vapor deposition route. Under local light excitation, the detected microphotoluminescence from any positions along the length of these whiskers exhibits strong and multi-mode trap-state whispering-gallery (WG) mode emission. With elevating the pumping power, some of these WG modes start lasing at an ultra-low threshold, with lasing wavelength covering a broad range from ∼540 to ∼750 nm. Calculations using a plane-wave model of WG modes show that all these trap-state lasing modes are transverse magnetic polarized, which was well explained by a two-dimensional finite element simulation. The surface doped semiconductor structures have potential applications as low-threshold tunable micro/nanoscale lasers in optical storage, lighting, and optical communications.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking

Fundamental limits in the external quantum efficiency of single nanowire solar cells

Martin Heiss and Anna Fontcuberta i Morral

Appl. Phys. Lett. 99, 263102 (2011); http://dx.doi.org/10.1063/1.3672168 (3 pages) | Cited 7 times

Online Publication Date: 27 December 2011

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The fundamental limits for the measurement of the efficiency of single nanowire solar cell devices are presented. We evaluate the effect of the substrate, light polarization, and existence of Mie resonances in the absorption of the solar spectrum for nanowires with diameters from 10 to 300 nm. We find that the efficiency measured under such configuration can be underestimated between a factor 1.6 and 7.0 for GaAs nanowires and between 6.7 and 15.9 for silicon nanowires. These results constitute a reference for understanding the limits in the measurement of single nanowire devices.
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88.40.jj Silicon solar cells

Evolution of sheet resistance of thin Ni film deposited on porous anodic alumina substrate

Aree Song, Chul Sung Kim, and Taejoon Kouh

Appl. Phys. Lett. 99, 263103 (2011); http://dx.doi.org/10.1063/1.3672211 (4 pages) | Cited 1 time

Online Publication Date: 28 December 2011

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We have investigated the evolution of sheet resistance of thin nickel films, thermally evaporated on porous alumina substrates, based on in situ electron transport measurement. By comparing the porous films, having various surface area fractions, to the uniform film, following the scaling law in metal-insulator transition, we have been able to describe the growth and the resulting thickness-dependent sheet resistance of the porous film in light of the two-dimensional percolation model. The underlying pore array strongly affects the appearance of the film conductance, and the study suggests the possibility of modulating the electron transport characteristics with the constrained surface geometry.
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73.61.At Metal and metallic alloys
68.55.A- Nucleation and growth
81.15.Dj E-beam and hot filament evaporation deposition

Dependence of carbon nanotube field effect transistors performance on doping level of channel at different diameters: On/off current ratio

Shaahin G. Shirazi and Sattar Mirzakuchaki

Appl. Phys. Lett. 99, 263104 (2011); http://dx.doi.org/10.1063/1.3672220 (3 pages)

Online Publication Date: 28 December 2011

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Choosing a suitable doping level of channel relevant to channel diameter is considered for determining the carbon nanotube field effect transistors’ performance which seem to be the best substitute of current transistor technology. For low diameter values of channel, the ratio of on/off current declines by increasing the doping level. But for higher diameter values, there is an optimum point of doping level in obtaining the highest on/off current ratio. For further verification, the variations of performance are justified by electron distribution function’s changes on energy band diagram of these devices. The results are compared at two different gate fields.
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85.35.Kt Nanotube devices
85.30.Tv Field effect devices
85.40.Ry Impurity doping, diffusion and ion implantation technology

Room-temperature quantum-dot-like luminescence from site-controlled InGaN quantum disks

L. K. Lee, Lei Zhang, Hui Deng, and P.-C. Ku

Appl. Phys. Lett. 99, 263105 (2011); http://dx.doi.org/10.1063/1.3672441 (4 pages)

Online Publication Date: 28 December 2011

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We studied the optical properties of site-controlled InGaN quantum disks fabricated by the top-down approach. Room-temperature quantum-dot-like photoluminescence was observed from a single InGaN quantum disk. Size-dependent emission wavelength shift was measured and attributed to the quantum confinement in the disk plane. Theoretical modeling was carried out to explain the large blue shift due to size quantization. Temperature dependent luminescence was characterized and showed an abnormally large linewidth at low temperature and a linewidth saturation above 100 K. A sidewall charge center model was proposed to explain these phenomena.
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78.67.Hc Quantum dots
78.20.N- Thermo-optic effects
78.55.Cr III-V semiconductors

Simultaneous step meandering and bunching instabilities controlled by Ehrlich-Schwoebel barrier and elastic interaction

Yan-Mei Yu, Axel Voigt, Xiaoshu Guo, and Yong Liu

Appl. Phys. Lett. 99, 263106 (2011); http://dx.doi.org/10.1063/1.3666781 (3 pages) | Cited 3 times

Online Publication Date: 29 December 2011

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Through phase-field simulations, we investigate simultaneous step meandering and bunching instabilities with the presence of Ehrlich-Schwoebel barrier and elastic interaction. The meandering instability induced by the Ehrlich-Schwoebel barrier is found to be dependent on the elastic interaction at low adatom deposition rate. The ordered step meandering-bunching structure is designed by using the predefined magnitude distribution of the force monopoles on vicinal surfaces based on interplay between the Ehrlich-Schwoebel barrier and the elastic interaction.
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68.35.Ct Interface structure and roughness
68.35.Fx Diffusion; interface formation
81.40.Jj Elasticity and anelasticity, stress-strain relations

Electrical noise characteristics of a doped silicon microcantilever heater-thermometer

Elise A. Corbin and William P. King

Appl. Phys. Lett. 99, 263107 (2011); http://dx.doi.org/10.1063/1.3673279 (3 pages)

Online Publication Date: 29 December 2011

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We measure the electrical noise characteristics of doped silicon microcantilevers during cantilever self-heating over the temperature range 296–781 K. The dominant noise source is 1/f below about 10 kHz, while at higher frequency, the dominant noise source is Johnson noise. The 1/f noise matches the Hooge model. The noise floor is about 10 nV/Hz1/2 and depends upon temperature, matching the theoretical Johnson noise. The Johnson noise-limited temperature resolution is about 1 μK/Hz1/2.
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07.10.Cm Micromechanical devices and systems
05.40.Ca Noise
07.20.Dt Thermometers
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