APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

31 Jan 1994

Volume 64, Issue 5, pp. 533-667

Page 2 of 2 Pages Previous Page | Jump to Page

Characterization of Si/Si1−xGex/Si quantum wells by cathodoluminescence imaging and spectroscopy

V. Higgs, E. C. Lightowlers, X. Xiao, and J. C. Sturm

Appl. Phys. Lett. 64, 607 (1994); http://dx.doi.org/10.1063/1.111064 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Cathodoluminescence (CL) imaging and spectroscopy have been used to characterize fully strained SiGe quantum wells grown on Si. At T≊5 K, the CL spectra contain only band edge luminescence features. Monochromatic imaging with the no‐phonon line attributed to the bound excitons in the quantum well, has shown that the distribution of the luminescence from the wells is not uniform. The thinnest well (33 Å) contained a low density of nonradiative (luminescence reduction up to 100%) spots 40–100 μm in size. The thickest well (500 Å) contained similar nonradiative spots and also dark line features oriented along the 〈110〉 directions. These dark line features are areas of nonradiative recombination (up to 70%) and have been identified by transmission electron microscopy as misfit dislocations.
Show PACS
78.60.Hk Cathodoluminescence, ionoluminescence
78.66.Li Other semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Surface resonant tunneling transistor: A new negative transconductance device

Ç. Kurdak, D. C. Tsui, S. Parihar, M. B. Santos, H. C. Manoharan, S. A. Lyon, and M. Shayegan

Appl. Phys. Lett. 64, 610 (1994); http://dx.doi.org/10.1063/1.111065 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
A new three‐terminal device, the surface resonant tunneling transistor, is realized by the molecular beam epitaxial cleaved edge overgrowth technique in the GaAs/AlGaAs system. The device exhibits negative transconductance as well as negative differential resistance. Some possibilities for future applications of the device to low‐power logic circuits are discussed.
Show PACS
73.40.Gk Tunneling
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

Photoluminescence and Raman studies of porous silicon in polymethyl methacrylate

S. Guha, G. Hendershot, D. Peebles, P. Steiner, F. Kozlowski, and W. Lang

Appl. Phys. Lett. 64, 613 (1994); http://dx.doi.org/10.1063/1.111066 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
We report the observation of strong luminescence from porous Si grains containing Si nanocrystallites embedded in polymethyl methacrylate disks. In concentrated samples, forward and backscattered photoluminescence spectra were just as strong as in porous Si on Si wafers. This new result indicates that porous Si grains could be embedded in nonconducting polymers and would retain all its inherent characteristics as in porous Si layers on Si wafers.
Show PACS
78.55.Hx Other solid inorganic materials

Doped microcrystalline silicon growth by high frequency plasmas

R. E. Hollingsworth and P. K. Bhat

Appl. Phys. Lett. 64, 616 (1994); http://dx.doi.org/10.1063/1.111067 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
The growth of boron‐ and phosphorus‐doped microcrystalline silicon films on glass using plasma enhanced chemical vapor deposition at high rf frequencies was examined for substrate temperatures from room temperature to 400 °C. Microcrystalline growth was obtained by heavy hydrogen dilution of silane with phosphine or trimethylboron as the doping gas. A maximum conductivity of 8 (Ω cm)−1 was obtained at a substrate temperature of 180 °C for p‐type films and 74 (Ω cm)−1 at 210 °C for n‐type films.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.61.Cw Elemental semiconductors

New method to improve thermal stability in the interface of silicon and tungsten by the interposition of plasma deposited tungsten nitride thin film

Chang Woo Lee, Yong Tae Kim, and Jeong Yong Lee

Appl. Phys. Lett. 64, 619 (1994); http://dx.doi.org/10.1063/1.111068 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
Thermally stable tungsten nitride/tungsten bilayer has been proposed for the application of metallization. This bilayer is sequentially formed by plasma enhanced chemical vapor deposition without breaking vacuum. The Rutherford backscattering spectrometry and cross‐sectional transmission electron microscopy reveal that the interaction between the W and Si substrate can be prevented by interposing a 800‐Å‐thick W67N33 layer. The W67N33/W bilayer maintains the integrity of the interface during annealing at 850 °C for 30 min without the formation of Si2W and interdiffusion phenomena. Sheet resistivity of the W67N33/W bilayer is gradually decreased from 17 to 12 μΩ cm at annealing temperatures up to 850 °C.
Show PACS
68.35.Fx Diffusion; interface formation
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
73.40.Ns Metal-nonmetal contacts

Difference‐frequency generation and sum‐frequency generation near the band gap of zincblende crystals

X.‐C. Zhang, Y. Jin, K. Ware, X. F. Ma, A. Rice, D. Bliss, J. Larkin, and M. Alexander

Appl. Phys. Lett. 64, 622 (1994); http://dx.doi.org/10.1063/1.111069 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
We present recent experimental results of difference‐frequency generation (DFG) and sum‐frequency generation (SFG) from zincblende materials. We measure the radiation field of difference‐frequency generation and the radiation intensity of sum‐frequency generation versus crystallographic orientation and fundamental photon energy. The simultaneous measurement of the angular dependence of polarized DFG and SFG is well characterized by the bulk second‐order nonlinearity calculation. Pronounced resonant behaviors near the GaAs band gap for both radiations (DFG and SFG) are compared.
Show PACS
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Hydrophobic silicon wafer bonding

Q.‐Y. Tong, E. Schmidt, U. Gösele, and M. Reiche

Appl. Phys. Lett. 64, 625 (1994); http://dx.doi.org/10.1063/1.111070 (3 pages) | Cited 41 times

Full Text: | Download PDF

Show Abstract
Wafers prepared by an HF dip without a subsequent water rinse were bonded at room temperature and annealed at temperatures up to 1100 °C. Based on substantial differences between bonded hydrophilic and hydrophobic Si wafer pairs in the changes of the interface energy with respect to temperature, secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM), we suggest that hydrogen bonding between Si‐F and H‐Si across two mating wafers is responsible for room temperature bonding of hydrophobic Si wafers. The interface energy of the bonded hydrophobic Si wafer pairs does not change appreciably with time up to 150 °C. This stability of the bonding interface makes reversible room‐temperature hydrophobic wafer bonding attractive for the protection of silicon wafer surfaces.
Show PACS
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
81.65.-b Surface treatments
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Electrical and optical properties of selectively doped Al0.25Ga0.75As/InyGa1−yAs (0.25≤y≤0.45) pseudomorphic heterostructures grown by molecular‐beam epitaxy

Makoto Kudo, Tomoyoshi Mishima, and Mineo Washima

Appl. Phys. Lett. 64, 628 (1994); http://dx.doi.org/10.1063/1.111071 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Electrical and optical properties of highly strained selectively doped Al0.25Ga0.75As/InyGa1−yAs (0.25≤y≤0.45) pseudomorphic heterostructures grown by molecular‐beam epitaxy are investigated. At a low growth temperature of 400 °C, the In mole fraction exceeds than 0.30 without degrading crystalline quality. The maximum mobility and sheet electron concentration at room temperature reach 6560 cm2/(V s) (y=0.34) and 2.94×1012 cm−2 (y=0.425), respectively. Photoluminescence measurements confirm the In mole fraction. This work suggests that InyGa1−yAs channels (y≳0.3) grown at 400 °C improve the performance of high‐electron‐mobility transistors.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Cr III-V semiconductors
73.61.Ey III-V semiconductors

Cryogenic field‐effect transistor with single electronic charge sensitivity

D. J. Mar, R. M. Westervelt, and P. F. Hopkins

Appl. Phys. Lett. 64, 631 (1994); http://dx.doi.org/10.1063/1.111072 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
We have fabricated matched pairs of cryogenic field‐effect transistors with input charge sensitivity qn=0.01 e/√Hz at T=1.3 K, low input capacitance 0.4 pF, and extremely high input resistance in excess of 1015 Ω. Low leakage permits dc charge‐coupled operation for times up to ∼103 s. The channel noise is characterized by a flat spectrum at high frequencies, and 1/f noise below a corner frequency fc<1 kHz. These devices can resolve charge differences as small as qn√fc=0.4e.
Show PACS
85.30.Tv Field effect devices
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
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Epitaxial YBa2Cu3O7−δ thin films on SrRuO3/Pt/MgO

P. Tiwari, X. D. Wu, S. R. Foltyn, M. Q. Le, I. H. Campbell, R. C. Dye, and R. E. Muenchausen

Appl. Phys. Lett. 64, 634 (1994); http://dx.doi.org/10.1063/1.111965 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
Epitaxial YBa2Cu3O7−δ (YBCO) thin films were deposited on (100) MgO using platinum and SrRuO3 (SRO) buffer layers by pulsed laser deposition. The films were (001) textured normal to substrate surface with a high degree of in‐plane orientation with respect to the substrate’s major axes. YBCO films showed superconducting transition temperature (Tco) at 91 K and critical current densities were found to be 2–3×106 A/cm2 at 77 K and zero field. An ion beam minimum channeling yield of 16% was obtained for YBCO films, indicating high crystallinity. The orientation relationship for this epitaxial multilayer structure was found to be (100) YBCO∥(100) SRO∥(100)Pt∥(100) MgO. This result showed that high‐quality superconducting thin films can be deposited on metal with an appropriate buffer layer.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
68.55.-a Thin film structure and morphology

Phase locking in two‐junction systems of high‐temperature superconductor‐normal metal‐superconductor junctions

C. D. Reintsema, R. H. Ono, T. E. Harvey, N. Missert, and L. R. Vale

Appl. Phys. Lett. 64, 637 (1994); http://dx.doi.org/10.1063/1.111073 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Mutual phase locking between two high‐temperature step‐edge superconducting‐normal metal‐superconducting junctions has been investigated using a two‐junction circuit with a nonsuperconducting feedback path. The strength of the phase‐locked state has been characterized as a function of locking frequency and temperature. Results are presented for a planar circuit as well as for a multilayer circuit incorporating a superconducting ground plane. The observed behavior was significantly enhanced for the circuit over a ground plane. Characterization of the phase locked state at 4 K yielded locking strengths as large as ‖IL‖/mathc=9%, and maximum locking frequencies to 1.06 THz. The magnitude of the locking strength decreased rapidly with increasing temperature with complete loss of coherence occurring at temperatures greater than 35 K.
Show PACS
85.25.Cp Josephson devices
74.50.+r Tunneling phenomena; Josephson effects
74.45.+c Proximity effects; Andreev reflection; SN and SNS junctions
74.78.-w Superconducting films and low-dimensional structures

Densification effect on the microstructure and critical current density in (Bi,Pb)2Sr2Ca2Cu3OxAg sheathed tape

M. Satou, Y. Yamada, S. Murase, T. Kitamura, and Y. Kamisada

Appl. Phys. Lett. 64, 640 (1994); http://dx.doi.org/10.1063/1.111074 (3 pages) | Cited 37 times

Full Text: | Download PDF

Show Abstract
The density of oxide core in (Bi,Pb)2Sr2Ca2Cu3OxAg sheathed tape was estimated from Vickers hardness and found to be increased to as high as 93% of the theoretical density with increasing the degree of cold working. During heat treatment, this densification before heat treatment promoted the formation of a strong linked microstructure which is characterized by dense microstructure, a high degree of orientation of oxide crystal and smooth interface between the Ag sheath and oxide core. Consequently, we obtained high values of critical current density: 66 000 A/cm2 at 0 T and 14 500 A/cm2 at 1 T for 77 K.
Show PACS
84.71.Mn Superconducting wires, fibers, and tapes
74.25.Sv Critical currents
74.72.-h Cuprate superconductors
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Laser patterning of Y‐Ba‐Cu‐O thin‐film devices and circuits

Roman Sobolewski, W. Xiong, W. Kula, and J. R. Gavaler

Appl. Phys. Lett. 64, 643 (1994); http://dx.doi.org/10.1063/1.111075 (3 pages) | Cited 31 times

Full Text: | Download PDF

Show Abstract
We report our studies on electrical properties of Y‐Ba‐Cu‐O test devices and circuits fabricated using a laser‐writing patterning technique. The patterning procedure is noninvasive, does not require a patterning mask, and does not contaminate nor damage the surface of patterned films. Our laser‐written, oxygen‐rich lines (typically 4–100 μm wide) possess excellent superconducting properties with zero resistivity at 89.5 K and critical current densities of above 2 MA/cm2 at 77 K. On the other hand, oxygen‐poor regions are semiconducting and exhibit thermally activated transport, well described by a three‐dimensional, variable‐length hopping process. Their resistance below 100 K is above 10 MΩ/square. A number of test structures patterned by laser writing, such as a microbridge, coplanar transmission line, open‐ended microwave resonator, photoconductive switch, and Y‐Ba‐Cu‐O field‐effect transistor, have been presented.
Show PACS
85.25.-j Superconducting devices
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.65.-b Surface treatments
74.78.-w Superconducting films and low-dimensional structures

Effect of elongation of the c‐cell dimension on intrinsic pinning in Bi2Sr2CaCu2Ox single crystals

Ryoji Funahashi, Ichiro Matsubara, Hiroshi Yamashita, and Tomoji Kawai

Appl. Phys. Lett. 64, 646 (1994); http://dx.doi.org/10.1063/1.111076 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A change of the intrinsic pinning strength by elongation of the c‐cell dimension in Bi2Sr2CaCu2Ox whiskers of single crystals has been studied by magnetic relaxation and irreversibility temperature (Tirr) measurements in the magnetic fields parallel to the a‐axis. When the c‐cell dimension is elongated by annealing under a reduced pressure, the intrinsic pinning strength is weakened. This result is consistent with an intrinsic pinning model.
Show PACS
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.72.-h Cuprate superconductors

Effect of using pure ozone on in situ molecular beam epitaxy of YBa2Cu3O7−x thin films at low pressure

Akihito Sawa, Haruhiko Obara, and Shin Kosaka

Appl. Phys. Lett. 64, 649 (1994); http://dx.doi.org/10.1063/1.111077 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
We studied the effect of ozone on molecular beam epitaxy (MBE) of YBa2Cu3O7−x (YBCO) films. The minimal ozone flux required for in situ synthesis of YBCO films was discussed taking into account the influences of kinetics and thermodynamics. Films were deposited at various growth rates and with various ozone fluxes on MgO(100) substrates at 650 °C. The minimal ozone flux required for in situ growth of YBCO films increased linearly with increasing growth rate. We suggest that in situ MBE growth of YBCO thin films with ozone is kinetically limited by the ozone‐to‐metal reaction ratio.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Photoinduced superconductivity and structural changes in high temperature superconducting films

David Lederman, J. Hasen, Ivan K. Schuller, E. Osquiguil, and Y. Bruynseraede

Appl. Phys. Lett. 64, 652 (1994); http://dx.doi.org/10.1063/1.111078 (3 pages) | Cited 34 times

Full Text: | Download PDF

Show Abstract
The illumination of PryGd1−yBa2Cu3Ox semiconducting and superconducting thin films increases their critical temperatures and decreases their normal state resistivities if and only if the films are oxygen deficient. Moreover, these changes are enhanced near the Pr‐induced metal‐insulator transition. Light also causes a contraction of the c‐axis in YBa2Cu3Ox which is correlated with the observed photoinduced resistivity changes. These changes are similar to those observed when oxygen‐deficient YBa2Cu3Ox is enriched with oxygen or annealed at room temperature after quenching from high temperatures.
Show PACS
74.72.-h Cuprate superconductors
74.78.-w Superconducting films and low-dimensional structures
74.25.F- Transport properties
74.62.-c Transition temperature variations, phase diagrams

Element specific magnetic domain imaging from an antiferromagnetic overlayer system

T. Kachel, W. Gudat, and K. Holldack

Appl. Phys. Lett. 64, 655 (1994); http://dx.doi.org/10.1063/1.111079 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Magnetic circular dichroism in resonant photoemission combined with a space resolving photoelectron spectrometer has been applied to measure magnetic domain structures with a spatial resolution of ≊10 μm. The tunability of the photon energy and the kinetic energy of photoelectrons provides a high degree of element specifity and magnetic contrast. We have applied the technique to 1 monolayer Gd on Fe(100) which allowed to measure magnetic domains in the Gd overlayer independently from the domains of the Fe substrate. Due to the antiferromagnetic coupling between Fe and Gd and because of the element specifity we could observe inverted domain images for the substrate and the overlayer.
Show PACS
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.60.Ch Domain walls and domain structure
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)

Subharmonic instability taking into account higher harmonics

E. Serrano, M. Carrascosa, F. Agulló‐López, and L. Solymar

Appl. Phys. Lett. 64, 658 (1994); http://dx.doi.org/10.1063/1.111080 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
It is shown that a large number of higher harmonics are needed for determining a region of subharmonic instability. For the examples calculated, the final result is qualitatively similar to that obtained considering only the imposed interference pattern.
Show PACS
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Simple scaling law for positron stopping in multilayered systems

G. C. Aers

Appl. Phys. Lett. 64, 661 (1994); http://dx.doi.org/10.1063/1.111081 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
Using a simple model to take into account the backscattering effects of interfaces we have developed a scheme which removes the necessity for time‐consuming Monte Carlo calculations in the generation of positron stopping profiles in multilayer systems. This scheme uses tabulated mean depth and backscattering fraction data for positrons in the materials constituting the multilayer and represents a computation time saving of several orders of magnitude. This makes detailed multilayer defect profiling with positrons a practical possibility.
Show PACS
78.70.Bj Positron annihilation
71.60.+z Positron states
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.85.+p Channeling phenomena (blocking, energy loss, etc.)

Langmuir–Blodgett technique without solvent

K. Hasegawa, K. Hosoi, A. Tomioka, and K. Miyano

Appl. Phys. Lett. 64, 664 (1994); http://dx.doi.org/10.1063/1.111082 (3 pages)

Full Text: | Download PDF

Show Abstract
A new Langmuir–Blodgett (LB) technique has been developed in which molecules are dispersed on the water surface by evaporation. Films of materials hard to dissolve in conventional volatile solvents can thus be formed and be transferred onto solid substrates. As a demonstration, unsubstituted quinacridone LB films have been formed.
Show PACS
68.18.-g Langmuir-Blodgett films on liquids
68.55.-a Thin film structure and morphology
FREE

Comment on ‘‘Buffer‐induced modulation of carrier density and mobility in a selectively doped heterostructure’’ [Appl. Phys. Lett. 61, 2308 (1992)]

T. H. H. Vuong, C. L. Reynolds, and J. Singleton

Appl. Phys. Lett. 64, 667 (1994); http://dx.doi.org/10.1063/1.111083 (1 page) | Cited 1 time

Full Text: | Download PDF

Abstract Unavailable
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.61.Ey III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close