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

19 Sep 1994

Volume 65, Issue 12, pp. 1477-1596

Page 2 of 2 Pages Previous Page | Jump to Page

Spiral growth of GaAs by molecular beam epitaxy

C. C. Hsu, J. B. Xu, I. H. Wilson, T. G. Andersson, and J. V. Thordson

Appl. Phys. Lett. 65, 1552 (1994); http://dx.doi.org/10.1063/1.112941 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Steps of monolayer height (0.28 nm) were observed by atomic force microscopy on a GaAs surface grown by molecular beam epitaxy. The monolayer terrace width between steps was found to be as large as 1000 nm in some areas. Surface reconstruction affects the surface diffusion process during growth and the shape of the step edges. Growth spirals were observed. Spirals originate from screw dislocations. The growth mechanism is according to the Burton–Cabrera–Frank theory.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)

Increasing short minority carrier diffusion lengths in solar‐grade polycrystalline silicon by ultrasound treatment

S. S. Ostapenko, L. Jastrzebski, J. Lagowski, and B. Sopori

Appl. Phys. Lett. 65, 1555 (1994); http://dx.doi.org/10.1063/1.112942 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
We have found that ultrasound treatment (UST) has a profound effect on the recombination rate in as‐grown, B‐doped cast polycrystalline silicon wafers for photovoltaic applications. As determined by surface photovoltage measurements of the minority carrier diffusion length L, the UST increases the corresponding lifetime by almost an order of magnitude. The maximum enhancement takes place in the wafer regions with the shortest L values. For L≳20 μm, both positive and negative changes of L after UST are revealed at different wafer regions. The UST effect is temperature dependent and exhibits maximum influence at about 60 °C. Enhanced dissociation of Fe‐B pairs by UST is identified as a mechanism which leads to a negative change of large L values, and a complex post‐treatment relaxation. A positive change of L is attributed to the influence of ultrasound vibrations on crystallographic defects.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
71.55.Cn Elemental semiconductors
72.40.+w Photoconduction and photovoltaic effects
61.72.Yx Interaction between different crystal defects; gettering effect

Temperature dependence of second harmonic generation from Si(100)(2×1) surfaces

H. B. Jiang, Y. H. Liu, X. Z. Lu, W. C. Wang, J. B. Zheng, and Z. M. Zhang

Appl. Phys. Lett. 65, 1558 (1994); http://dx.doi.org/10.1063/1.112943 (2 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Our experiments on reconstructed Si(100)(2×1) surfaces revealed that the reflected second harmonic (SH) signals at 532 nm originated from the contribution of the electrons in surface states. The SH intensity was inversely proportional to the square of the sample temperature. A preliminary explanation for this temperature dependence was proposed.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
73.25.+i Surface conductivity and carrier phenomena
78.66.Db Elemental semiconductors and insulators

Two‐photon intersubband transitions in quantum well infrared photoconductors

E. Dupont, P. Corkum, H. C. Liu, P. H. Wilson, M. Buchanan, and Z. R. Wasilewski

Appl. Phys. Lett. 65, 1560 (1994); http://dx.doi.org/10.1063/1.113004 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
We demonstrate that a symmetric GaAs/GaAlAs quantum well photodetector with a peak responsivity centered at 8.1 μm shows a significant quadratic power response at 10.6 μm. This is due to intersubband two‐photon transitions from the ground level to continuum states. The two‐photon responsivity agrees with a theoretical prediction based on a perturbative approach and photoconductive gain estimations.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
78.66.Fd III-V semiconductors
72.40.+w Photoconduction and photovoltaic effects

Enhancement mode metal‐semiconductor field effect transistors using homoepitaxial diamonds

Hiroshi Kawarada, Makoto Aoki, and Masahiro Ito

Appl. Phys. Lett. 65, 1563 (1994); http://dx.doi.org/10.1063/1.112915 (3 pages) | Cited 57 times

Full Text: | Download PDF

Show Abstract
Enhancement mode‐type metal‐semiconductor field effect transistors using diamond have been fabricated. The transistor operation is based on the control of surface p‐type conduction of a hydrogen terminated homoepitaxial layer. Boron doping was not used for the conduction. An aluminum contact is used for the Schottky gate and gold ohmic contacts are used for the source and drain. The obtained transconductance is 20–200 μs/mm using aluminum gates of 10–40 μm in length. The active region on the homoepitaxial layer is thin enough for the total depletion of carriers when the gate bias is zero.
Show PACS
85.30.Tv Field effect devices
73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.-c Electronic transport in interface structures

In situ spectroscopic ellipsometry of porous silicon layers annealed under ultrahigh vacuum

A. Larré, A. Halimaoui, F. Glowacki, F. Ferrieu, Y. Campidelli, and D. Bensahel

Appl. Phys. Lett. 65, 1566 (1994); http://dx.doi.org/10.1063/1.112916 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
In situ spectroscopic ellipsometry measurements in the 1.8–2.8 eV spectral range were performed on porous silicon (PS) layers annealed in an ultrahigh vacuum chamber up to 600 °C. It is shown that both the refractive index and the absorption coefficient increase after the thermal anneal and the effect is reversible when samples are returned to atmosphere and HF dipped. These changes in the optical properties of the material can be attributed to an intrinsic strain modification in the PS cellular structure induced by hydrogen desorption upon annealing.
Show PACS
78.66.-w Optical properties of specific thin films
81.40.Tv Optical and dielectric properties related to treatment conditions
78.55.Hx Other solid inorganic materials

Maskless patterning of silicon surface based on scanning tunneling microscope tip‐induced anodization and chemical etching

Hiroyuki Sugimura, Takuma Yamamoto, Nobuyuki Nakagiri, Masayuki Miyashita, and Tetsuji Onuki

Appl. Phys. Lett. 65, 1569 (1994); http://dx.doi.org/10.1063/1.112917 (3 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
A microprocessing method for silicon (Si) without photolithography is proposed. The method consists of only two processes. Hydrogen‐terminated Si surfaces (Si‐H) were first locally anodized using scanning tunneling microscopy (STM). The non‐anodized surfaces were then etched chemically in potassium hydroxide solution. The anodic oxide produced with the first process performed as an etching mask. The height of the etched pattern of approximately 50 nm was much larger than the thickness of the anodic oxide. Humidity effect on STM tip‐induced anodization of Si‐H is also shown. The area of the anodization was enlarged with increasing humidity, and the spatial resolution became worse.
Show PACS
81.65.-b Surface treatments
85.40.Hp Lithography, masks and pattern transfer
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

Fluorine enhanced oxidation of silicon at low temperatures

A. Kazor, C. Jeynes, and Ian W. Boyd

Appl. Phys. Lett. 65, 1572 (1994); http://dx.doi.org/10.1063/1.112918 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
We report the oxidation of silicon at and below 550 °C in a mixture of oxygen and fluorine. Introduction of small concentrations of fluorine (<0.1%) in the oxygen ambient increases the oxide growth sharply to rates in excess of 8 Å/min where the average fluorine concentration in the oxide can exceed 6 at. %. For each oxidation temperature there was a unique fluorine concentration at which the oxidation rate was at its highest. Fluorine depth profiles in the film were determined by high depth resolution nuclear reaction analysis, and high interface concentrations of fluorine were observed.
Show PACS
81.65.-b Surface treatments

Radiation‐induced defects in Czochralski‐grown silicon doped with germanium

K. Schmalz and V. V. Emtsev

Appl. Phys. Lett. 65, 1575 (1994); http://dx.doi.org/10.1063/1.112919 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The formation of vacancy‐oxygen complexes (A centers) in Czochralski (Cz)‐grown silicon (Cz‐Si) with Ge content of 1018–1020 cm−3 due to gamma irradiation was studied by deep level transient spectroscopy and Hall effect measurements. It was found that the A centers are not formed at the beginning of gamma irradiation and can be developed afterward only. In this case, the formation of A centers in irradiated Cz‐Si:Ge is thought to be a result of annealing of specific radiation induced defects.
Show PACS
61.72.J- Point defects and defect clusters
61.80.Ed γ-ray effects
71.55.Cn Elemental semiconductors

Interface roughness scattering in thin, undoped GaInP/GaAs quantum wells

W. C. Mitchel, G. J. Brown, Ikai Lo, Said Elhamri, Mohamed Ahoujja, K. Ravindran, R. S. Newrock, Manijeh Razeghi, and Xiaguang He

Appl. Phys. Lett. 65, 1578 (1994); http://dx.doi.org/10.1063/1.112920 (3 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
Electronic transport properties of very thin undoped GaInP/GaAs quantum wells have been measured by temperature dependent low field Hall effect and by Shubnikov–de Haas effect. Strong Shubnikov–de Haas oscillations were observed after increasing the electron concentration via the persistent photocurrent effect. Low temperature mobilities of up to 70 000 cm2/V s at carrier concentrations of 6.5×1011 cm−2 were observed in a 20 Å quantum well. The results are compared with the theory of interface roughness scattering which indicates extremely smooth interfaces; however, discrepancies between experiment and theory are observed.
Show PACS
73.50.Bk General theory, scattering mechanisms
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Dn Low-field transport and mobility; piezoresistance

Laser ablation threshold of YBa2Cu3O6+x

B. Dam, J. Rector, M. F. Chang, S. Kars, D. G. de Groot, and R. Griessen

Appl. Phys. Lett. 65, 1581 (1994); http://dx.doi.org/10.1063/1.112921 (3 pages) | Cited 32 times

Full Text: | Download PDF

Show Abstract
Using projection optics we made a detailed study of the interaction of a spatially uniform 248 nm excimer laser beam and a 99% dense YBa2Cu3O6+x target. Below a threshold fluence of 1 J/cm2 the roughness of the irradiated target increases dramatically due to non‐stoichiometric ablation. The overall target surface composition becomes increasingly Y rich and Cu poor, while the opposite is found for the corresponding ablated thin films. Above the threshold fluence the composition of the ablated target surface is conserved. As a result of the energy homogeneity of the laser beam obtained by means of projection optics, the optimization of the deposition parameters has been improved leading to the reproducible fabrication of flat, stoichiometric YBa2Cu3O7 films with Tc0’s over 91 K.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
81.15.Fg Pulsed laser ablation deposition
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Transport through 90° [010] basal‐plane‐faced tilt and twist grain boundaries in YBa2Cu3O7−δ thin films

D. J. Lew, Y. Suzuki, A. F. Marshall, T. H. Geballe, and M. R. Beasley

Appl. Phys. Lett. 65, 1584 (1994); http://dx.doi.org/10.1063/1.112969 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
We have fabricated controlled grain boundaries between a‐ and c‐axis films of YBa2Cu3O7−δ (YBCO). By selectively depositing c‐axis and in‐plane aligned a‐axis YBCO on the same substrate, we have grown nominally 90° [010] basal‐plane‐faced tilt and twist grain boundaries (BFGB’s and TGB’s) on LaSrGaO4 (LSGO) substrates and have studied their transport. We find that the TGB is very robust, exhibiting high critical current density Jc and weak field dependence, and is as well coupled as our [010] antiphase boundaries. The BFGB is not as strong, but couples better than high‐angle [001] tilt grain boundaries in c‐axis films. Although the BFGB’s do limit Jc, they do not reduce Jc by more than an order of magnitude and the field dependence is very weak. We discuss these grain boundaries in terms of weak links.
Show PACS
74.50.+r Tunneling phenomena; Josephson effects
74.25.Sv Critical currents
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.72.-h Cuprate superconductors

Increased transition temperature in in situ coevaporated YBa2Cu3O7−δ thin films by low temperature post‐annealing

S. J. Berkowitz, E. De Obaldia, K. F. Ludwig, W. J. Skocpol, P. M. Mankiewich, R. H. Ono, J. A. Beall, L. R. Vale, D. A. Rudman, M. L. O’Malley, L. M. Drabeck, and P. A. Polakos

Appl. Phys. Lett. 65, 1587 (1994); http://dx.doi.org/10.1063/1.112922 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
In situ coevaporated YBa2Cu3O7−δ thin films have a slightly depressed transition temperature Tc, though they have excellent radio‐frequency surface resistance characteristics. These films consistently have less orthorhombic strain than laser ablated or post‐annealed films. Low temperature (320–420 °C) post‐annealing of in situ coevaporated films in 100 kPa of O2 raised Tc to values as high as 91.5 K with some increase in the orthorhombic strain. All measured thin films show less variation of Tc with orthorhombic strain than does bulk material.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.62.Bf Effects of material synthesis, crystal structure, and chemical composition

The electrostatic polarization of ferroelectric liquid crystals: A new interpretation of the triangle‐wave technique

J. Ruth, J. V. Selinger, and R. Shashidhar

Appl. Phys. Lett. 65, 1590 (1994); http://dx.doi.org/10.1063/1.112923 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We show that the electrostatic polarization measured in ferroelectric liquid crystals using the standard triangle‐wave technique is not the total polarization of the sample, but rather a specific nonlinear component of the total polarization. We present a Landau theory to calculate this nonlinear component explicitly. In the high‐temperature limit, above the smectic‐A–smectic‐C∗ phase transition, the theory predicts that the observed polarization scales as E3/(T−TAC)4, where T is the temperature and E the applied electric field. In the low‐temperature limit, the observed polarization approaches the total polarization. These theoretical predictions are consistent with experimental measurements.
Show PACS
61.30.-v Liquid crystals
77.80.-e Ferroelectricity and antiferroelectricity
77.22.Ej Polarization and depolarization
77.84.Nh Liquids, emulsions, and suspensions; liquid crystals

Single‐walled carbon nanotubes growing radially from YC2 particles

Dan Zhou, Supapan Seraphin, and Su Wang

Appl. Phys. Lett. 65, 1593 (1994); http://dx.doi.org/10.1063/1.112924 (3 pages) | Cited 41 times

Full Text: | Download PDF

Show Abstract
In the primary soot produced by arc discharge using an yttrium carbide loaded anode, bundles of single‐walled carbon nanotubes (SWT) are observed, protruding radially from YC2 particles coated with graphitic multilayers. The graphitic cages separating YC2 particle and SWT bundles fall into the narrow range of 10–20 layers. The morphology of the clusters suggests a two‐step growth model: The radial SWT growth pattern is first initiated by catalytic action between the YC2 droplet and the carbon in the gas phase. Second, and upon cooling, the graphitic cage starts by segregating excess carbon from the YC2 bulk, arresting further growth of SWT.
Show PACS
61.46.-w Structure of nanoscale materials
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
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
FREE

Erratum: ‘‘As/P interdiffusion in ultrathin InAs/InP strained quantum wells’’ [Appl. Phys. Lett. 65, 341 (1994)]

J. M. Sallese, S. Taylor, H. J. Bühlmann, J. F. Carlin, A. Rudra, R. Houdré, and M. Ilegems

Appl. Phys. Lett. 65, 1596 (1994); http://dx.doi.org/10.1063/1.113090 (1 page)

Full Text: | Download PDF

Show Abstract
The intermixing process of ultrathin InAs/InP strained quantum well structures by thermal annealing at 730–830 °C is investigated by photoluminescence measurements. Analyzing the results using a microscopic model, the interdiffusion process is characterized by an activation energy close to 3.8±0.2 eV, leading to an interdiffusion coefficient close to 7±0.5×10−17 cm2/s at 830 °C.
Show PACS
66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation
78.55.Hx Other solid inorganic materials
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
99.10.Cd Errata
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close