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16 Oct 1995

Volume 67, Issue 16, pp. 2263-2418

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High second‐harmonic conversion efficiency of quasi‐phase‐matched LiTaO3 waveguides pumped by single‐mode pulsed AlGaAs laser diodes

A. Azouz, N. Stelmakh, J.‐M. Lourtioz, D. Delacourt, D. Papillon, and J. Lehoux

Appl. Phys. Lett. 67, 2263 (1995); http://dx.doi.org/10.1063/1.115120 (3 pages) | Cited 2 times

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We show that the averaged second‐harmonic conversion efficiency of quasi‐phase‐matched LiTaO3 waveguides can be increased by a factor larger than 15 with the use of single‐mode pulsed AlGaAs laser diodes as the optical sources. The proton exchange followed by thermal annealing is used both to periodically change the sign in d33 nonlinear coefficient and to fabricate the waveguides. Laser pulses are produced by strong rf modulation of the diode current while single‐mode operation is achieved with a grating‐tuned external cavity. The averaged conversion efficiency is found to linearly increase with peak power of pulses even in the case of pulses whose spectral width is larger than the spectral acceptance of LiTaO3 waveguides. Experimental results are in agreement with calculated ones. The conversion efficiency of 450 %/W presently reached at optimum (i.e., 1% for 2.2 mW pump and 1 cm interaction length) is among the highest performances reported to date for frequency doubling of laser diodes. © 1995 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.55.Rz Doped-insulator lasers and other solid state lasers
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Lifetime determination for high‐lying excited states using Z scan

Tai‐Huei Wei, Tzer‐Hsiang Huang, Huang‐Der Lin, and Sheng‐Hsien Lin

Appl. Phys. Lett. 67, 2266 (1995); http://dx.doi.org/10.1063/1.115121 (3 pages) | Cited 31 times

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We report a method of determining the lifetimes of the high‐lying excited singlet states of dye molecules in solution. The method is based on the Z‐scan technique and the observation of saturation of excited state absorption in dye solutions using laser pulses having Gaussian temporal and spatial distributions. This leads to the important finding that the use of laser pulses as long as tens of picosecond can resolve subpicosecond lifetimes. The method is demonstrated by measuring an upper excited singlet state lifetime of 900 fs using 30 ps full width at half maximum input pulses on a chloroaluminum phthalocyanine dye. © 1995 American Institute of Physics.
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33.70.Ca Oscillator and band strengths, lifetimes, transition moments, and Franck-Condon factors
33.80.Rv Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Ray optics model and numerical computations for the radiation pressure micromotor

Robert C. Gauthier

Appl. Phys. Lett. 67, 2269 (1995); http://dx.doi.org/10.1063/1.115122 (3 pages) | Cited 34 times

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In this letter, the spinning of a micron sized radiation pressure motor is analyzed using geometrical optics to model for interactions of a highly focused laser beam with the medium discontinuities. The motor’s direction of rotation and dependence on focused beam parameters, predicted from the computations, are in agreement with previously published experimental results. The motor can be made to rotate in the clockwise or counterclockwise direction by changing the ambient medium only. © 1995 American Institute of Physics.
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06.60.Sx Positioning and alignment; manipulating, remote handling
07.10.Cm Micromechanical devices and systems
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy

Nonlinear optical polymers with dipole moment aligned transverse to main chain

Naoto Tsutsumi, Osamu Matsumoto, Wataru Sakai, and Tsuyoshi Kiyotsukuri

Appl. Phys. Lett. 67, 2272 (1995); http://dx.doi.org/10.1063/1.115123 (3 pages) | Cited 8 times

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A new type of nonlinear optical (NLO) polymer for second harmonic generation is presented. This type of NLO polymer has a large dipole moment which is aligned transverse to the main chain. Poled polymer shows a large second order nonlinearity of 1.6×10−7 esu (67 pm/V). Good thermal stability of nonlinearity was observed in ambient condition. © 1995 American Institute of Physics.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Jk Polymers and organics
78.66.Qn Polymers; organic compounds

Study on self‐built optical path production in Ce‐doped BaTiO3 stimulated photorefractive scattering self‐pumped phase conjugator

Xiaodong Mu, Zongshu Shao, Jingwen Zhang, Liangmin Zhang, Minhua Jiang, Haosu Luo, and Weizhuo Zhong

Appl. Phys. Lett. 67, 2275 (1995); http://dx.doi.org/10.1063/1.115124 (3 pages) | Cited 2 times

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The observations on the stimulated photorefractive scattering self‐pumped phase conjugator (SPS‐SPPC) in Ce‐doped BaTiO3 demonstrate that the self‐built pumped paths in the SPS‐SPPC are induced by the scattering seeds. Using these results, a formation mechanism of the SPS‐SPPC is presented, which is related to the scattering seeds, the contradirectional two‐wave mixing, and four‐wave mixing. The production conditions of the pumped paths are also given. The studies show that both too short and too long distances from the scattering seed to the region of the four‐wave mixing will bring about a failure in building the optical paths, and the large backscattering coefficient is always advantageous to produce these paths. © 1995 American Institute of Physics.
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42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Ultrafast intensity switching and nonthermal carrier effects in semiconductor microcavity lasers

Frank Jahnke and Stephan W. Koch

Appl. Phys. Lett. 67, 2278 (1995); http://dx.doi.org/10.1063/1.115125 (3 pages) | Cited 16 times

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A microscopic nonequilibrium theory is applied to investigate the dynamical response of semiconductor microcavity lasers for ultrashort optical pulse excitation. It is predicted that femtosecond pulse induced carrier heating leads to picosecond switching and recovery of the laser emission. © 1995 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Single‐layer white light‐emitting organic electroluminescent devices based on dye‐dispersed poly(N‐vinylcarbazole)

J. Kido, H. Shionoya, and K. Nagai

Appl. Phys. Lett. 67, 2281 (1995); http://dx.doi.org/10.1063/1.115126 (3 pages) | Cited 343 times

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Bright single‐layer white light‐emitting organic electroluminescent devices were developed by using dye‐dispersed poly(N‐vinylcarbazole) (PVK). The active layer consists only of one polymer layer that is simply sandwiched between two electrodes, indium‐tin oxide, and Mg:Ag. In order to achieve bipolarity in the single polymer emitter layer, PVK was molecularly dispersed with electron‐transporting additives such as 2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole. In addition, several fluorescent dyes, having different emission colors, were dispersed as emitting centers. By adjusting the concentration of the fluorescent dyes, white light with a maximum luminescence of 4100 cd/m2 was obtained, which is the brightest white light ever observed for organic electroluminescent devices. © 1995 American Institute of Physics.
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42.70.Jk Polymers and organics
85.60.Jb Light-emitting devices

Open‐core screw dislocations in GaN epilayers observed by scanning force microscopy and high‐resolution transmission electron microscopy

W. Qian, G. S. Rohrer, M. Skowronski, K. Doverspike, L. B. Rowland, and D. K. Gaskill

Appl. Phys. Lett. 67, 2284 (1995); http://dx.doi.org/10.1063/1.115127 (3 pages) | Cited 111 times

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Structural investigations of organometallic vapor phase epitaxy grown α‐GaN films using high‐resolution transmission electron microscopy and scanning force microscopy have revealed the presence of tunnel‐like defects with 35–500 Å radii that are aligned along the growth direction of the crystal and penetrate the entire epilayer. These defects, which are termed ‘‘nanopipes,’’ terminate on the free surface of the film at the centers of hexagonal growth hillocks and form craters with 600–1000 Å radii. Either one or two pairs of monolayer‐height spiral steps were observed to emerge from the surface craters which allowed us to conclude that nanopipes are the open cores of screw dislocations. The measured dimensions of the defects are compared to Frank’s theory for the open‐core dislocation. © 1995 American Institute of Physics.
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68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
68.55.-a Thin film structure and morphology

Pseudomorphic Si1−xSnx alloy films grown by molecular beam epitaxy on Si

S. Yu. Shiryaev, J. Lundsgaard Hansen, P. Kringhøj, and A. Nylandsted Larsen

Appl. Phys. Lett. 67, 2287 (1995); http://dx.doi.org/10.1063/1.115128 (3 pages) | Cited 19 times

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Strained Si1−xSnx (0.001≤x≤0.052) alloys were synthesized on (001) Si substrates by molecular beam epitaxy at 220 and 280 °C. The as‐grown alloys were found to be pseudomorphic to Si with no indication of extended defects and tin precipitates. Within the accuracy of our studies the compressive strain in the alloys corresponds to that deduced from Vegard’s linear interpolation between the lattice parameters of Si and α‐Sn. The annealing experiments show that the alloys are thermally unstable at a higher temperature (1000 °C) and that the transition of the Si1−xSnx/Si system to a lower energy state occurs through two channels: (i) alloy decomposition through precipitation of tin atoms into metallic β‐Sn, and (ii) introduction of 60° misfit dislocations. © 1995 American Institute of Physics.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology
68.60.Dv Thermal stability; thermal effects

Effect of pressure on the crystallization of amorphous Fe–Mo–Si–B alloy with diffusion reaction at its surface

Bin Yao, Bingzhe Ding, Aimin Wang, and Zhuangqi Hu

Appl. Phys. Lett. 67, 2290 (1995); http://dx.doi.org/10.1063/1.115129 (3 pages) | Cited 1 time

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The amorphous (Fe0.99,Mo0.01)78Si9B13 alloy with diffusion reaction with Al at its surface transformed into α‐Fe(Al) solid solution under 4 GPa and α‐Fe(Mo,Si) and (Fe,Mo)3B or Fe2B under other pressures at a temperature range of 783–933 K. A thermodynamic mechanism was suggested by discussing the changes of the chemical potentials with pressure. © 1995 American Institute of Physics.
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81.30.-t Phase diagrams and microstructures developed by solidification and solid-solid phase transformations

Stability hierarchy of the pseudomorphic FeSi2 phases: α, γ, and defected CsCl

Leo Miglio, Francesca Tavazza, and Giovanna Malegori

Appl. Phys. Lett. 67, 2293 (1995); http://dx.doi.org/10.1063/1.115130 (3 pages) | Cited 15 times

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We present a total‐energy stability diagram of FeSi2 phases which explains the recent experimental findings of pseudomorphic epitaxy on Si(111), depending on film thickness and growth conditions. In particular, our tight binding calculations point out that the appearance of the fluorite structure (γ) at very low coverages can only be attributed to a binding energy with the silicon substrate sizeably larger than tetragonal (α) and CsCl‐defected phases. © 1995 American Institute of Physics.
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61.50.Lt Crystal binding; cohesive energy
68.55.-a Thin film structure and morphology

The microstructural stability of Al(Cu) lines during electromigration

T. M. Shaw, C‐K. Hu, K. Y. Lee, and R. Rosenberg

Appl. Phys. Lett. 67, 2296 (1995); http://dx.doi.org/10.1063/1.115131 (3 pages) | Cited 15 times

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We have used transmission electron microscopy to examine in detail how microstructural changes take place in aluminum/copper lines adjacent to tungsten contacts during electromigration testing. Observations made on aluminum‐4% copper lines show that significant changes in the grain structure surrounding precipitates occur during testing even under conditions where grain growth is not normally observed in the lines. Grain coarsening and precipitate growth produced by the applied current result in the formation of new diffusion blocking structures in the lines which are likely to significantly influence their time to failure. © 1995 American Institute of Physics.
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66.30.J- Diffusion of impurities
66.30.Qa Electromigration
81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging
85.40.Ls Metallization, contacts, interconnects; device isolation

Deposition of continuous and well adhering diamond films on steel

A. Fayer, O. Glozman, and A. Hoffman

Appl. Phys. Lett. 67, 2299 (1995); http://dx.doi.org/10.1063/1.115132 (3 pages) | Cited 42 times

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The present work reports a successful solution to the problem of diamond deposition onto steel. This was achieved through the use of an intermediate layer between the substrate and the deposited film. The intermediate layer consisted of a 10 μm thick nitridized chromium film. The chromium film was produced by electrochemical deposition and the nitridation was performed in an ammonia flow. This nitridation process results in the formation of mixed CrN and Cr2N crystalline phases, with the latter in contact with the steel substrate. During diamond deposition, partial carbidization of the chromium nitride interlayer took place resulting in the formation of a layer composed mainly of carbides and carbon phases onto which continuous diamond films were deposited. Beneath the carburized region a chromium nitride‐rich phase, consisting predominantly of Cr2N, was observed. The diamond films were deposited using a hot filament system at a rate of 1 μm per hour and a substrate temperature of 800 °C. The toughness of the diamond films was evaluated by measuring the minimum load necessary to induce delamination with a cone‐shaped diamond indenter. No delamination events occurred during indentation up to loads of 1000 N. The samples were examined by Auger electron spectroscopy, x‐ray diffraction, Raman spectroscopy, and scanning electron microscopy. It is suggested that chromium nitride interlayers could be employed in the deposition of diamond films on iron based alloys for industrial purposes. © 1995 American Institute of Physics.
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68.35.Fx Diffusion; interface formation
68.55.-a Thin film structure and morphology
68.55.Nq Composition and phase identification
81.15.Jj Ion and electron beam-assisted deposition; ion plating

The role of the surface in transient enhanced diffusion

D. R. Lim, C. S. Rafferty, and F. P. Klemens

Appl. Phys. Lett. 67, 2302 (1995); http://dx.doi.org/10.1063/1.115133 (3 pages) | Cited 50 times

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The enhanced diffusion of impurities that is seen following ion implantation is rapidly quenched, hence, the name transient enhanced diffusion (TED). The quenching of TED is associated with the annealing of implant damage, either by the diffusion of point defects to the bulk or to the surface. It is variously assumed that either the surface or the bulk is the predominant annealing site. In this work, we explore these assumptions by observing the reduction of TED in a buried marker, when the surface is etched to bring it closer to implanted damage. The results show a considerable reduction in TED with surface etching, demonstrating that the surface plays a key role in annealing implant damage. Numerical modeling allows extraction of the surface recombination length of interstitials at 800 °C. Only a value of 0.1 μm is consistent with the data. All but a very small fraction of implanted interstitials are recombined at the surface with this value. © 1995 American Institute of Physics.
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61.72.uf Ge and Si
66.30.J- Diffusion of impurities
81.65.-b Surface treatments

Integrated micro‐scanning tunneling microscope

Y. Xu, N. C. MacDonald, and S. A. Miller

Appl. Phys. Lett. 67, 2305 (1995); http://dx.doi.org/10.1063/1.115134 (3 pages) | Cited 21 times

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Two versions of micro‐scanning tunneling microscopes (micro‐STMs) have been fabricated. The integrated micro‐STMs are fabricated from single crystal silicon using the high‐aspect‐ratio SCREAM process. Each micro‐STM includes integrated xy comb drive actuators and a torsional z actuator with integrated cantilever and tip. One micro‐STM measures approximately 200 μm on‐a‐side and is an example of a STM element for a STM array architecture. Another, larger micro‐STM/atomic force microscope measures 2 mm on‐a‐side including a 1 mm long cantilever with a 20 nm diam tip. We demonstrate the operation of this larger STM by obtaining a STM image of a 200 nm metal conductor on a silicon chip. © 1995 American Institute of Physics.
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07.79.Cz Scanning tunneling microscopes
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices

Kinetics and nucleation model of the C49 to C54 phase transformation in TiSi2 thin films on deep‐sub‐micron n+ type polycrystalline silicon lines

J. A. Kittl, D. A. Prinslow, P. P. Apte, and M. F. Pas

Appl. Phys. Lett. 67, 2308 (1995); http://dx.doi.org/10.1063/1.115135 (3 pages) | Cited 64 times

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A detailed kinetic study of the C49 to C54 phase transformation in TiSi2 thin films was performed, to obtain the full time, temperature, and linewidth dependence of the fraction transformed during rapid thermal annealing on patterned deep‐sub‐micron lines. A Johnson–Mehl–Avrami kinetic analysis showed Avrami exponents of 0.8±0.2 for all submicron lines and 1.9±0.2 for a 40 μm side square structure. The activation energy of 3.9 eV was independent of linewidth. Transformation times increased dramatically as linewidth decreased. A kinetic model based on the density of nucleation sites as a function of linewidth and C49 grain size is proposed and shown to fit the data. © 1995 American Institute of Physics.
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68.35.Rh Phase transitions and critical phenomena
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder

Electroplating of poly(tetrafluoroethylene) using plasma enhanced chemical vapor deposited titanium nitride as an interlayer

A. Weber, A. Dietz, R. Pöckelmann, and C.‐P. Klages

Appl. Phys. Lett. 67, 2311 (1995); http://dx.doi.org/10.1063/1.115136 (3 pages) | Cited 1 time

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A low‐temperature process for titanium nitride (TiN) deposition by means of an electron cyclotron resonance (ECR) plasma enhanced chemical vapor deposition process was applied to poly(tetrafluoroethylene) (PTFE). Tetrakis(dimethylamido)titanium introduced into the downstream region of a nitrogen ECR plasma was used as a precursor for TiN deposition at 100 °C. The thin TiN films (thickness 15–30 nm) act as interlayers to activate the electroless deposition of copper followed by an electroplating process. Prior to the deposition of the interlayer, the samples were treated on a biased susceptor with argon ions to enhance the adhesion of the TiN interlayer. This metallization procedure avoids the use of toxic and pollutive etching agents and yields adherent copper layers on PTFE. Films were characterized by four‐point probe resistivity measurements, atomic force microscopy, and secondary ion mass spectrometry. © 1995 American Institute of Physics.
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52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

A gas phase chemical etchant for boron nitride films

Stephen J. Harris, Gary L. Doll, Derek C. Chance, and Anita M. Weiner

Appl. Phys. Lett. 67, 2314 (1995); http://dx.doi.org/10.1063/1.115137 (3 pages) | Cited 15 times

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We have demonstrated that boron nitride films deposited on silicon and tantalum can be etched in a hot filament environment with an input gas composition of 1% methane in hydrogen. Etching experiments were carried out at around 800 K on a tantalum foil and at somewhat higher temperatures on silicon substrates. If the etchant is atomic hydrogen or methyl radical, then we estimate etching efficiencies (atoms etched per collision) of ∼10−5 or 10−4 for these species, respectively. © 1995 American Institute of Physics.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.65.-b Surface treatments

Relaxation mechanism of Ge islands/Si(001) at low temperature

F. K. LeGoues, J. Tersoff, M. C. Reuter, M. Hammar, and R. Tromp

Appl. Phys. Lett. 67, 2317 (1995); http://dx.doi.org/10.1063/1.115138 (3 pages) | Cited 32 times

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Strained layers generally relax by dislocation glide. Here, using UHV‐TEM, we study growth of Ge islands on Si(001) at ≲350 °C. We find that, although conventional relaxation (i.e., via glide of 60° dislocations) is suppressed, the islands grow relaxed from the outset, by direct incorporation of sessile 90° dislocations into the edge of the growing island. Paradoxically, the low‐temperature islands are more fully relaxed than those grown at higher temperature. © 1995 American Institute of Physics.
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68.55.-a Thin film structure and morphology

Graded‐composition buffer layers using digital AlGaAsSb alloys

I. J. Fritz, L. R. Dawson, J. A. Olsen, and A. J. Howard

Appl. Phys. Lett. 67, 2320 (1995); http://dx.doi.org/10.1063/1.114331 (3 pages) | Cited 2 times

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We describe step‐graded digital‐alloy buffers using alternate layers of Al0.5Ga0.5As and Al0.5Ga0.5As0.65Sb0.35 grown on GaAs substrates by molecular beam epitaxy. The buffers consist of three sets of superlattices with AlGaAs/AlGaAsSb layer thicknesses of 7.7/2.3 nm, 5.4/4.6 nm, and 3.1/6.9 nm, respectively, terminating in a lattice constant equal to that of bulk In0.32Ga0.68As. Transmission electron micrographs show that most of the misfit‐generated dislocations lie near the steps in pseudoalloy composition, and atomic force micrographs indicate a rms surface roughness of 3.6 nm. A 20.5‐period lattice‐matched InGaAs/InAlAs reflector stack grown on such a buffer has a peak reflectivity of 98% near 1.3 μm. These buffers provide potentially useful substrates for optoelectronic device applications near 1.3 μm using strained InGaAs active regions. © 1995 American Institute of Physics.
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68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Band edge discontinuities between microcrystalline and amorphous hydrogenated silicon alloys and their effect on solar cell performance

X. Xu, J. Yang, A. Banerjee, S. Guha, K. Vasanth, and S. Wagner

Appl. Phys. Lett. 67, 2323 (1995); http://dx.doi.org/10.1063/1.114332 (3 pages) | Cited 23 times

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We have used internal photoemission measurements to determine the electrical band gap of microcrystalline p‐type layers used in a‐Si:H alloy solar cells, and the band edge discontinuities of the conduction and the valence bands between μc‐Si:H and a‐Si:H alloys. The band gap ofμc‐Si:H is found to be around 1.6 eV, and the discontinuities at the conduction and the valence band edges are −0.02 and 0.26 eV, respectively. Use of these parameters in the numerical simulation of single‐junction a‐Si:H alloy solar cells is found to accurately predict the experimental results of solar cell performance. © 1995 American Institute of Physics.
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73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
84.60.Jt Photoelectric conversion

Far‐infrared emission spectroscopy of hot two‐dimensional plasmons in Al0.3Ga0.7As/GaAs heterojunctions

K. Hirakawa, K. Yamanaka, M. Grayson, and D. C. Tsui

Appl. Phys. Lett. 67, 2326 (1995); http://dx.doi.org/10.1063/1.114333 (3 pages) | Cited 33 times

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We have investigated the radiative decay of hot two‐dimensional (2D) plasmons in Al0.3Ga0.7As/ GaAs heterostructures by far‐infrared emission spectroscopy and determined the spectral line shape of the radiation. Narrowband plasmon emission lines are obtained in the terahertz regime. The experimentally observed energies of plasmon emission are in good agreement with the results of a recently developed full grating theory. The plasmon emission intensity is found to increase with increasing input electrical power to the electron system and follows the Bose–Einstein distribution law characterized by the electron temperature of the hot 2D electron system. This fact indicates that 2D plasmons are thermally excited in the present experimental regime. © 1995 American Institute of Physics.
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73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.30.Fs III-V and II-VI semiconductors

Dry etch damage in InN, InGaN, and InAlN

S. J. Pearton, J. W. Lee, J. D. MacKenzie, C. R. Abernathy, and R. J. Shul

Appl. Phys. Lett. 67, 2329 (1995); http://dx.doi.org/10.1063/1.114334 (3 pages) | Cited 48 times

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Changes in conductivity of InN, In0.5Ga0.5N, and In0.5Al0.5N layers exposed to Ar plasmas under both electron cyclotron resonance and reactive ion etching conditions have been measured as a function of rf power, pressure, and exposure time. The combination of high microwave and high rf powers produces large increases (10–104 times) in sheet resistance of the nitrides, but conditions more typical of real etching processes (rf power <150 W) do not change the electrical properties. The nitrides are more resistant to damage introduction than other III–V semiconductors. The removal of damage‐related traps occurs with an activation energy of ∼2.7 eV. © 1995 American Institute of Physics.
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71.55.Eq III-V semiconductors
72.80.Ey III-V and II-VI semiconductors
81.65.-b Surface treatments

All solid source molecular beam epitaxy growth of strained‐layer InGaAs/GaInAsP/GaInP quantum well lasers (λ=980 nm)

Mika Toivonen, Marko Jalonen, Arto Salokatve, Jari Näppi, Pekka Savolainen, Markus Pessa, and Harry Asonen

Appl. Phys. Lett. 67, 2332 (1995); http://dx.doi.org/10.1063/1.114335 (3 pages) | Cited 9 times

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We report on the growth of 980‐nm strained‐layer InGaAs/GaInAsP/GaInP separated confinement quantum well lasers using all solid source molecular beam epitaxy. Valved cracker cells were employed for both phosphorus and arsenic. Fabricated lasers exhibited excellent performance that is comparable to similar lasers grown by gas source molecular beam epitaxy in our laboratory. A maximum output power of 450 mW and over 250 mW in single mode operation was achieved for ridge waveguide lasers with AR/HR coated facets. © 1995 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Cr III-V semiconductors
85.60.Jb Light-emitting devices

Fabrication of large area silicon solar cells by rapid thermal processing

S. Sivoththaman, W. Laureys, J. Nijs, and R. Mertens

Appl. Phys. Lett. 67, 2335 (1995); http://dx.doi.org/10.1063/1.114336 (3 pages) | Cited 6 times

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Large area n+pp+ solar cells have been fabricated on 10 cm×10 cm pseudo‐quasi‐square CZ silicon wafers (1 Ω cm, p‐type) predominantly used by the photovoltaic (PV) industry. All the high‐temperature steps have been performed by rapid thermal processing (RTP). Emitter formation, back surface field (BSF) formation, and surface oxidation have been performed in just two RTP steps each lasting 50 s. Solar cells of 15% efficiency have been fabricated this way, demonstrating the applicability of this low thermal budget technology to large area, modulable size, industrial quality Si wafers. Furthermore, the rapid thermal oxidation (RTO) is shown to result in good quality thin oxides with Si/SiO2 interface trap densities (Dit)<1011 cm−3 eV−1 near‐midgap. © 1995 American Institute of Physics.
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73.50.Pz Photoconduction and photovoltaic effects
81.40.Gh Other heat and thermomechanical treatments
84.60.Jt Photoelectric conversion
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