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15 Dec 1997

Volume 71, Issue 24, pp. 3465-3583

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High-temperature persistent spectral hole burning of Eu3+-doped SiO2 glass prepared by the sol-gel process

Masayuki Nogami and Yoshihiro Abe

Appl. Phys. Lett. 71, 3465 (1997); http://dx.doi.org/10.1063/1.120361 (3 pages) | Cited 25 times

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Persistent spectral hole burning was observed at temperatures higher than 77 K in SiO2 glass doped with the Eu3+ ions. The Eu3+-doped SiO2 glass was prepared using the sol-gel process of Si(OC2H5)4 and EuCl3⋅6H2O. A persistent spectral hole was burned in the excitation spectrum of the 7F0→5D0 transition of Eu3+ using a Rhodamine 6G dye laser, of which the hole width and depth were 1.6 cm−1 and ∼ 20% of the total intensity, respectively, at 77 K. Hole depth decreased with increasing temperature and disappeared above ∼ 130 K. A possible mechanism for the hole burning is related to the local structure around Eu3+ and the residual OH and H2O in the glass. © 1997 American Institute of Physics.
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61.43.Fs Glasses
81.05.Kf Glasses (including metallic glasses)
42.50.Hz Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
81.10.Dn Growth from solutions
81.10.Fq Growth from melts; zone melting and refining
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)

Lateral electron current operation of vertical cavity surface emitting lasers with buried tunnel contact hole sources

J. J. Wierer, P. W. Evans, N. Holonyak, and D. A. Kellogg

Appl. Phys. Lett. 71, 3468 (1997); http://dx.doi.org/10.1063/1.120400 (3 pages) | Cited 20 times

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Vertical cavity surface emitting lasers (VCSELs) are demonstrated with reverse-biased tunnel contact junctions allowing low-loss lateral electron current to support hole injection. A compact hybrid vertical cavity is employed consisting of a lower 6.5 period AlxOy/GaAs distributed Bragg reflector (DBR) formed by selective oxidation of high Al composition AlxGa1−xAs, and an electron-beam deposited 5 period SiO2/Si upper DBR. The cavity (active region) is defined also by selectively oxidizing a current-confining aperture. Lateral electron current drives a tunnel contact junction providing hole injection underneath the upper DBR through the oxide-defined current aperture. The p-type crystal in the VCSEL is reduced to a minimum, thus reducing resistive loss and device voltage. © 1997 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems

Positron and gamma-photon production and nuclear reactions in cascade processes initiated by a sub-terawatt femtosecond laser

P. L. Shkolnikov, A. E. Kaplan, A. Pukhov, and J. Meyer-ter-Vehn

Appl. Phys. Lett. 71, 3471 (1997); http://dx.doi.org/10.1063/1.120362 (3 pages) | Cited 31 times

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We demonstrate theoretically that sub-terawatt lasers are capable of producing, through specially arranged cascade processes in optimal targets, substantial amounts of nuclear radiation (positrons, gamma-photons, neutrons, and fission fragments). © 1997 American Institute of Physics.
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23.20.Lv γ transitions and level energies

Electric field poling of flux grown KTiOPO4

H. Karlsson and F. Laurell

Appl. Phys. Lett. 71, 3474 (1997); http://dx.doi.org/10.1063/1.120363 (3 pages) | Cited 41 times

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A method to periodically pole conductive ferroelectric materials has been developed. With this method we have fabricated high quality domain inverted crystals of flux grown KTiOPO4 suitable for efficient quasi-phase matched frequency conversion. Samples have been evaluated by second harmonic generation and normalized conversion efficiencies up to 6.9%/W cm2 have been obtained. © 1997 American Institute of Physics.
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77.84.Fa KDP- and TGS-type crystals
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
77.22.Ej Polarization and depolarization
66.30.H- Self-diffusion and ionic conduction in nonmetals

Intersubband emission in double-well structures with quantum interference in absorption

Jérôme Faist, Federico Capasso, Carlo Sirtori, Albert L. Hutchinson, Ken W. West, and L. N. Pfeiffer

Appl. Phys. Lett. 71, 3477 (1997); http://dx.doi.org/10.1063/1.120364 (3 pages) | Cited 15 times

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Intersubband electroluminescence is investigated in structures where two excited states are coupled by tunneling to a common continuum, and exhibit a clear sign of destructive interference in absorption spectroscopy. We show that, in addition to the nonreciprocity between the matrix elements for absorption and emission, the difference between the absorption and emission profiles has its origin also in the electron distribution of the injector. © 1997 American Institute of Physics.
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78.60.Fi Electroluminescence
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.23.-b Electronic transport in mesoscopic systems
42.50.-p Quantum optics

Bright blue–green electroluminescence from aromatic polyimides

E. I. Mal’tsev, M. A. Brusentseva, V. A. Kolesnikov, V. I. Berendyaev, B. V. Kotov, and A. V. Vannikov

Appl. Phys. Lett. 71, 3480 (1997); http://dx.doi.org/10.1063/1.120365 (3 pages) | Cited 17 times

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New polyimide type of polymers, aromatic polyimides (APIs) containing sulphur atoms in the backbone, were investigated as electron-hole transporting and light-emitting materials for use in unilayer electroluminescent diodes. The simplicity of synthesis, high thermal stability, organic solvent solubility together with excellent film-forming properties make the APIs potentially of interest for technological applications. © 1997 American Institute of Physics.
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42.70.Jk Polymers and organics
78.60.Fi Electroluminescence
64.75.-g Phase equilibria
85.60.Jb Light-emitting devices

Midinfrared vertical-cavity surface-emitting laser

C. L. Felix, W. W. Bewley, I. Vurgaftman, J. R. Meyer, L. Goldberg, D. H. Chow, and E. Selvig

Appl. Phys. Lett. 71, 3483 (1997); http://dx.doi.org/10.1063/1.120366 (3 pages) | Cited 22 times

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We report a type-II antimonide midinfrared vertical-cavity surface-emitting laser. The emission wavelength of 2.9 μm is nearly independent of temperature (dλ/dT ≈ 0.07 nm/K) and the multimode linewidth is quite narrow (3.5 nm). The pulsed threshold power at 86 K is as low as 22 mW for a 30 μm spot. Lasing is observed up to T = 280 K, and the peak output power from a 600 μm spot exceeds 2 W up to 260 K. The differential power conversion efficiency is >1% at 220 K. © 1997 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
78.66.Fd III-V semiconductors

The influence of inversion domains on surface morphology in GaN grown by molecular beam epitaxy

L. T. Romano and T. H. Myers

Appl. Phys. Lett. 71, 3486 (1997); http://dx.doi.org/10.1063/1.120367 (3 pages) | Cited 42 times

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Growth of GaN by rf-plasma molecular beam leads to different surface morphologies for nitrogen-rich growth versus gallium-rich growth. Nitrogen-rich growth produces a significant density of pyramidal hillocks while gallium-rich growth results in flat surfaces. Differences in surface morphology were directly linked to the presence of inversion domains which originated in the nucleation layer. Nitrogen-rich growth and growth under atomic hydrogen enhanced the growth rate of inversion domains with respect to the surrounding matrix, while growth under Ga-rich conditions resulted in a more nearly equal growth rate. © 1997 American Institute of Physics.
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81.05.Ea III-V semiconductors
68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.35.B- Structure of clean surfaces (and surface reconstruction)
72.80.Ey III-V and II-VI semiconductors

Two types of spiral growth of C60 films on KBr(001)

Y. Kim, L. Jiang, T. Iyoda, K. Hashimoto, and A. Fujishima

Appl. Phys. Lett. 71, 3489 (1997); http://dx.doi.org/10.1063/1.120368 (3 pages) | Cited 2 times

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Two types of spiral growth, single and double spirals, of C60 epitaxial films on a KBr(001) substrate were observed by atomic force microscopy (AFM). These single and double spirals were found on films grown at different rates. All spiral islands show the threefold symmetry of the face-centered-cubic (fcc) structure. In the case of single spirals, many fringes were observed in three equivalent [110] directions on the fcc (111) surface. From the AFM images, we concluded that the growth process of these spirals can be explained by the classical crystal growth theory of Burton, Cabrera, and Frank and that screw dislocations form without any direct influence of the substrate. © 1997 American Institute of Physics.
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61.48.-c Structure of fullerenes and related hollow and planar molecular structures
81.05.ub Fullerenes and related materials
68.55.-a Thin film structure and morphology
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Nanoscale imaging of domain dynamics and retention in ferroelectric thin films

A. Gruverman, H. Tokumoto, A. S. Prakash, S. Aggarwal, B. Yang, M. Wuttig, R. Ramesh, O. Auciello, and T. Venkatesan

Appl. Phys. Lett. 71, 3492 (1997); http://dx.doi.org/10.1063/1.120369 (3 pages) | Cited 111 times

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We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We demonstrate that polarization reversal occurs under no external field (i.e., loss of remanent polarization) via a dispersive continuous-time random walk process, identified by a stretched exponential decay of the remanent polarization. © 1997 American Institute of Physics.
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77.55.-g Dielectric thin films
77.80.Dj Domain structure; hysteresis
77.65.Bn Piezoelectric and electrostrictive constants
77.22.Ej Polarization and depolarization
77.80.Fm Switching phenomena

Fast bistable nematic display with grey scale

R. Barberi, M. Giocondo, J. Li, R. Bartolino, I. Dozov, and G. Durand

Appl. Phys. Lett. 71, 3495 (1997); http://dx.doi.org/10.1063/1.120370 (3 pages) | Cited 25 times

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We present a novel principle for a fast bistable nematic display with intrinsic grey scale. The geometry of a single pixel is the usual hybrid texture in between two conductive flat plates. The device is written by creating surface walls when an electric field is applied, above the thresholds to achieve both the planar anchoring breaking and an electro-hydrodynamic flow. Erasing is obtained by simply breaking the anchoring in absence of vortices. The distorted regions around surface walls depolarize the incident light. As the surface defect density can be modulated, a grey scale is achieved. © 1997 American Institute of Physics.
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42.79.Kr Display devices, liquid-crystal devices
85.60.Pg Display systems
42.65.Pc Optical bistability, multistability, and switching, including local field effects

On the semiconducting state and structural properties of YH3 from first principles theory

R. Ahuja, B. Johansson, J. M. Wills, and O. Eriksson

Appl. Phys. Lett. 71, 3498 (1997); http://dx.doi.org/10.1063/1.120371 (3 pages) | Cited 34 times

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With the use of first principles theory we confirm the semiconducting ground state of the technologically interesting YH3 compound. Thus, unlike previously published theories, we demonstrate that density functional theory in the local density approximation reproduces the existence of a band gap. We also show that the HoD3 structure is the stable structure at ambient conditions, in agreement with experiment. In addition, we predict that moderate applied pressure will drive YH3 into the cubic structure. © 1997 American Institute of Physics.
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71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.20.Nr Semiconductor compounds

Formation of elemental Ag precipitates in AlGaAs by ion implantation and thermal annealing

J. C. P. Chang, J. Ye, M. R. Melloch, D. T. Crouse, and D. D. Nolte

Appl. Phys. Lett. 71, 3501 (1997); http://dx.doi.org/10.1063/1.120372 (3 pages)

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We report transmission electron microscopy (TEM) studies of precipitation in Ag-implanted and annealed Al0.3Ga0.7As. Silver was chosen because it does not form compounds with Ga and/or As when precipitating based on bulk thermodynamics arguments. TEM confirmed the formation of an elemental metal/semiconductor composite, which consists of nanometer-sized Ag (fcc structure) precipitates dispersed in the matrix. The precipitates are nonspherical and have an orientation relationship to Al0.3Ga0.7As of (200)Ag//(200)AlGaAs, (02-2)Ag//(02-2)AlGaAs, and [011]Ag//[011]AlGaAs. High temperature (900 °C) anneals transform the phase of the precipitate to hexagonal, Ag3(GaAl) compounds. This shape distribution has been correlated with inhomogeneous broadening of the optical absorption. © 1997 American Institute of Physics.
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61.72.uj III-V and II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
64.75.-g Phase equilibria
78.66.Fd III-V semiconductors
61.80.Jh Ion radiation effects
85.40.Ry Impurity doping, diffusion and ion implantation technology
81.30.Mh Solid-phase precipitation

Direct observation of Si lattice strain and its distribution in the Si(001)–SiO2 interface transition layer

Young Pil Kim, Si Kyung Choi, Hyun Kyong Kim, and Dae Won Moon

Appl. Phys. Lett. 71, 3504 (1997); http://dx.doi.org/10.1063/1.120373 (3 pages) | Cited 40 times

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In the transition layer of the Si(001)–SiO2 interface, Si lattice strain and its distribution were directly observed by medium energy ion scattering spectroscopy for thermal and ion beam oxides. The strain was in the vertical direction, and the maximum values at the SiO2 side of the transition layer were 0.96% and 2.8% for the thermal and ion beam oxides, respectively. © 1997 American Institute of Physics.
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68.35.Ct Interface structure and roughness
68.35.Gy Mechanical properties; surface strains
68.35.Fx Diffusion; interface formation
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity

Memory window of Pt/SrBi2Ta2O9/CeO2/SiO2/Si structure for metal ferroelectric insulator semiconductor field effect transistor

Yong Tae Kim and Dong Suk Shin

Appl. Phys. Lett. 71, 3507 (1997); http://dx.doi.org/10.1063/1.120374 (3 pages) | Cited 54 times

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We have proposed a Pt/SrBi2Ta2O9/CeO2/SiO2/Si structure for a ferroelectric gate of metal ferroelectric insulator field effect transistor. A memory window of the proposed ferroelectric gate increases as electric field applied to the SrBi2Ta2O9 layer increases, and the memory window of Pt/SrBi2Ta2O9/CeO2/SiO2/Si is relatively greater than that of Pt/SrBi2Ta2O9/SiO2/Si. As a result, the Pt/SrBi2Ta2O9(140 nm)/CeO2(25 nm)/SiO2/Si structure has sufficiently programmable memory windows from 0.9 to 2.5 V in the low gate voltage range of 4–7 V. © 1997 American Institute of Physics.
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85.30.Tv Field effect devices
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Growth of strain-relaxed Ge films on Si(001) surfaces

Akira Sakai, Toru Tatsumi, and Keiko Aoyama

Appl. Phys. Lett. 71, 3510 (1997); http://dx.doi.org/10.1063/1.120375 (3 pages) | Cited 24 times

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We have grown thin Ge films that were fully strain relaxed and had smooth surfaces on Si(001) surfaces without buffer layers by ultrahigh vacuum chemical vapor deposition. The procedure consists of layer-by-layer Ge growth with hydrogen-surfactant mediation and high-temperature ( ∼ 700 °C) post-growth annealing for strain relaxation. The key step is the formation of a thin (less than 1 nm thick) capping Si or SiGe layer on the layered Ge film before the annealing. This capping layer effectively suppresses clustering of Ge during the annealing, even at high temperatures. Cross-sectional transmission electron microscopy of annealed samples having a 20-nm-thick Ge film clearly revealed a periodic array of 90° full-edge dislocations with a Burgers vector of a/2〈110〉 type confined at the Ge/Si interface. This dislocation structure leads to efficient strain relaxation in the Ge film, which was also confirmed by x-ray diffraction measurement. © 1997 American Institute of Physics.
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81.05.Cy Elemental semiconductors
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.Cc Kinetics of defect formation and annealing
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

In situ imaging of polymer melt spreading with a high-temperature atomic force microscope

D. Glick, P. Thiansathaporn, and R. Superfine

Appl. Phys. Lett. 71, 3513 (1997); http://dx.doi.org/10.1063/1.120376 (3 pages) | Cited 2 times

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We have developed a method of imaging at high temperatures with atomic force microscopy using a laser to deliver heat to an area localized around the AFM tip–sample junction. We couple approximately 75 mW from an argon-ion laser into the active region to raise the temperature of a 100 nm gold film to around 225 °C. As a sample, we use 1.2 μm polystyrene spheres adsorbed onto the film. We image the flow of these spheres, in situ, over the course of an hour. The dynamics of the polymer spreading is shown to be consistent with the dry spreading of a precursor film. © 1997 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
68.08.Bc Wetting
61.25.H- Macromolecular and polymers solutions; polymer melts

Observation of the polarization of domains in ferroelectric thin films using x-ray interference

Carol Thompson, Christopher M. Foster, Jeffrey A. Eastman, and G. Brian Stephenson

Appl. Phys. Lett. 71, 3516 (1997); http://dx.doi.org/10.1063/1.120377 (3 pages) | Cited 16 times

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We report that the sign of the polarization of an epitaxial ferroelectric film can be determined from the interference between the x-ray scattering from the film and the substrate. X-ray scattering measurements of a 10 nm epitaxial PbTiO3 film grown by metal-organic chemical vapor deposition on a SrTiO3 substrate are presented. The scattering profile near the 001 peaks of the film and substrate shows clear evidence of the interference effects. Analysis indicates that this film is a single domain of specific polarity. © 1997 American Institute of Physics.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.22.Ej Polarization and depolarization
77.55.-g Dielectric thin films
77.80.Dj Domain structure; hysteresis
78.70.Ck X-ray scattering

Hydrogen-implant induced exfoliation of silicon and other crystals

C. M. Varma

Appl. Phys. Lett. 71, 3519 (1997); http://dx.doi.org/10.1063/1.120378 (3 pages) | Cited 29 times

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A simple theory is formulated in which the pressure of bubbles containing hydrogen molecules in the implanted region drives exfoliation due to the anisotropy of the elastic forces and the evaporation or slow diffusion of atomic hydrogen to molecular hydrogen in the bubbles leading to a catastrophic growth in the bubble radius and the molecular fraction as temperature increases. The process of blistering and cratering at small implant depths is also considered. Comparison to recent experiments is made. © 1997 American Institute of Physics.
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61.80.Jh Ion radiation effects
61.72.uf Ge and Si
61.72.Qq Microscopic defects (voids, inclusions, etc.)
66.30.J- Diffusion of impurities
61.82.Fk Semiconductors

Surface diffusion growth and stability mechanism of BN nanotubes produced by laser beam heating under superhigh pressures

Oleg A. Louchev

Appl. Phys. Lett. 71, 3522 (1997); http://dx.doi.org/10.1063/1.120379 (3 pages) | Cited 17 times

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A growth mechanism for BN nanotubes appearing at superhigh pressures under laser beam heating [D. Golberg, Y. Bando, M. Eremets, K. Takemura, K. Kurashima, and H. Yusa, Appl. Phys. Lett. 69, 2045 (1996)] is proposed based upon consideration of the dependence of the energy of adsorption and surface diffusion on the surface curvature. According to this mechanism, the growth of BN nanotubes is due to surface diffusion along the external surface, which also ensures morphological stability of the open end during growth. It is suggested that the observed nanotube heights are limited by the corresponding diffusion length. © 1997 American Institute of Physics.
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81.07.-b Nanoscale materials and structures: fabrication and characterization
61.46.-w Structure of nanoscale materials
68.35.Fx Diffusion; interface formation
62.50.-p High-pressure effects in solids and liquids
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.35.Md Surface thermodynamics, surface energies
82.60.Cx Enthalpies of combustion, reaction, and formation

Strain induced interface roughness of Si1−xCx δ layers on Si(001)

J. Falta, D. Bahr, A. Hille, G. Materlik, and H. J. Osten

Appl. Phys. Lett. 71, 3525 (1997); http://dx.doi.org/10.1063/1.120380 (3 pages) | Cited 3 times

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Ultra thin buried Si1−xCx films (δ layers) of monolayer thickness and high carbon concentration (x>0.1) in a Si matrix have been prepared by molecular beam epitaxy and were structurally characterized by high resolution x-ray diffraction, i.e., measurements of crystal truncation rods. The average interface roughness of the δ layers is in the order of 6–10 Å. A larger carbon deposit results in the formation of thicker Si1−xCx δ layers with lower carbon concentrations and smoother interfaces. This effect is attributed to a reduction of the strain in the δ layer due to the lower carbon concentration. © 1997 American Institute of Physics.
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68.35.Ct Interface structure and roughness
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties

Controlling charge injection in organic electronic devices using self-assembled monolayers

I. H. Campbell, J. D. Kress, R. L. Martin, D. L. Smith, N. N. Barashkov, and J. P. Ferraris

Appl. Phys. Lett. 71, 3528 (1997); http://dx.doi.org/10.1063/1.120381 (3 pages) | Cited 151 times

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We demonstrate control and improvement of charge injection in organic electronic devices by utilizing self-assembled monolayers (SAMs) to manipulate the Schottky energy barrier between a metal electrode and the organic electronic material. Hole injection from Cu electrodes into the electroluminescent conjugated polymer poly[2-methoxy,5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] was varied by using two conjugated-thiol based SAMs. The chemically modified electrodes were incorporated in organic diode structures and changes in the metal/polymer Schottky energy barriers and current–voltage characteristics were measured. Decreasing (increasing) the Schottky energy barrier improves (degrades) charge injection into the polymer. © 1997 American Institute of Physics.
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73.30.+y Surface double layers, Schottky barriers, and work functions
85.60.Jb Light-emitting devices
85.30.Tv Field effect devices

Low temperature formation of C54–TiSi2 using titanium alloys

C. Cabral, L. A. Clevenger, J. M. E. Harper, F. M. d’Heurle, R. A. Roy, C. Lavoie, K. L. Saenger, G. L. Miles, R. W. Mann, and J. S. Nakos

Appl. Phys. Lett. 71, 3531 (1997); http://dx.doi.org/10.1063/1.120401 (3 pages) | Cited 39 times

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We demonstrate that the temperature at which the C49 TiSi2 phase transforms to the C54 TiSi2 phase can be lowered more than 100 °C by alloying Ti with small amounts of Mo, Ta, or Nb. Titanium alloy blanket films, containing from 1 to 20 at. % Mo, Ta, or Nb were deposited onto undoped polycrystalline Si substrates. The temperature at which the C49–C54 transformation occurs during annealing at constant ramp rate was determined by in situ sheet resistance and x-ray diffraction measurements. Tantalum and niobium additions reduce the transformation temperature without causing a large increase in resistivity of the resulting C54 TiSi2 phase, while Mo additions lead to a large increase in resistivity. Titanium tantalum alloys were also used to form C54 TiSi2 on isolated regions of arsenic doped Si(100) and polycrystalline Si having linewidths ranging from 0.13 to 0.56 μm. The C54 phase transformation temperature was lowered by over 100 °C for both the blanket and fine line samples. As the concentration of Mo, Ta, or Nb in the Ti alloys increase, or as the linewidth decreases, an additional diffraction peak appears in in situ x-ray diffraction which is consistent with increasing amounts of the higher resistivity C40 silicide phase. © 1997 American Institute of Physics.
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68.35.Fx Diffusion; interface formation
64.70.K- Solid-solid transitions
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
61.72.Cc Kinetics of defect formation and annealing

Structural and electrical properties of low-temperature-grown Al(As,Sb)

H.-R. Blank, H. Kroemer, S. Mathis, and J. S. Speck

Appl. Phys. Lett. 71, 3534 (1997); http://dx.doi.org/10.1063/1.120382 (3 pages) | Cited 1 time

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We have investigated structural and electrical properties of Al(As,Sb) dual-anion compounds grown by molecular beam epitaxy at low substrate temperature. We find single-crystal growth down to substrate temperatures as low as 275 °C. Additional donor-type defects form when Al(As,Sb) is grown at 450 °C or less, with the defect density increasing with decreasing substrate temperature. We find no evidence for the formation of precipitates upon annealing low-temperature-grown (LTG) Al(As,Sb) in contrast to LTG arsenides. © 1997 American Institute of Physics.
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68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.61.Ey III-V semiconductors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
72.80.Ey III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
61.72.Cc Kinetics of defect formation and annealing
72.20.My Galvanomagnetic and other magnetotransport effects

Bilayer growth period oscillation of the Sb2 reactivity during molecular beam epitaxy of AlSb (001)

Ron Kaspi and John P. Loehr

Appl. Phys. Lett. 71, 3537 (1997); http://dx.doi.org/10.1063/1.120383 (3 pages) | Cited 6 times

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We report oscillations in Sb2 reactivity with the growth surface during layer-by-layer deposition of AlSb (001) by molecular beam epitaxy. Real-time measurements of the Sb desorption rate using line-of-sight mass spectrometry, in parallel with reflection high-energy electron diffraction specular beam intensity measurements, suggest that this behavior results from the periodic variation of the surface step density as these steps act as preferential adsorption sites for antimony. This is further supported by computer simulations that examine the surface step density as a function of bilayer coverage. © 1997 American Institute of Physics.
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81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.35.B- Structure of clean surfaces (and surface reconstruction)
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