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

17 Jan 1994

Volume 64, Issue 3, pp. 261-393

Page 1 of 2 Pages Next Page | Jump to Page

Semiconductor laser cavity dispersion measurement based on interferometric crosscorrelation of amplified spontaneous emission

Kazunori Naganuma

Appl. Phys. Lett. 64, 261 (1994); http://dx.doi.org/10.1063/1.111174 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
The Fourier transform of the interferometric crosscorrelation of amplified spontaneous emission (ASE) is proposed as a general‐purpose method for measuring cavity dispersion. The electric field correlation of the ASE from a cavity shows subfringes displaced from the ordinary interferogram by the cavity round‐trip time. The cavity transfer function is derived from the subfringe using the Fourier transform. This method is demonstrated on semiconductor devices. It provides a very quick way to measure round‐trip group delay dispersion as well as gain across a device’s whole gain band.
Show PACS
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes

Ultrabroadband second‐harmonic generation in organic and inorganic thin crystals

J. O. White, D. Hulin, M. Joffre, A. Migus, A. Antonetti, E. Toussaere, R. Hierle, and J. Zyss

Appl. Phys. Lett. 64, 264 (1994); http://dx.doi.org/10.1063/1.111175 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Organic thin crystals of 2‐methyl‐4‐nitroaniline (MNA) have been used to frequency double simultaneously all components of a broadband continuum using a non‐phase‐matched configuration. A 1 μm sample of MNA permits to convert, in a single pulse, wavelengths in the band 600–1400 nm to the 300–700 nm band. Using the same technique, we also evidence the remarkably large bandwidth of a 100‐μm‐thick KDP, when used in the wavelength noncritical phase‐matched region centered around 1.03 μm. The conversion efficiencies of the 1‐μm‐thick MNA sample and of the 100‐μm‐thick phase‐matched KDP crystal are shown to be comparable. The results are of interest to the processing and measurement of femtosecond pulses.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Thermomechanical data storage using a fiber optic stylus

S. Hoen, H. J. Mamin, and D. Rugar

Appl. Phys. Lett. 64, 267 (1994); http://dx.doi.org/10.1063/1.111176 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
We have developed a simple and fast surface modification technique for possible data storage applications. Writing is accomplished by heating the metallized tip of a tapered optical fiber with microsecond laser pulses. The heated tip, which is in contact with a polycarbonate substrate, creates a nanoindentation. Deflections of this same tip are used to detect the written marks, as in atomic force microscopy. The marks have sharp edges with 10%–90% transition widths of 0.2 μm, and have been written with laser pulses as short as 5 μs at repetition rates of 50 kHz. Readback has been performed over 300 kHz on a spinning sample. Substantial improvements in mechanical response and wear properties are seen compared to micromachined cantilevers.
Show PACS
42.79.Vb Optical storage systems, optical disks
42.81.-i Fiber optics
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
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

Time‐to‐frequency converter for measuring picosecond optical pulses

M. T. Kauffman, W. C. Banyai, A. A. Godil, and D. M. Bloom

Appl. Phys. Lett. 64, 270 (1994); http://dx.doi.org/10.1063/1.111177 (3 pages) | Cited 44 times

Full Text: | Download PDF

Show Abstract
We present a new technique for measuring the intensity I(t) of optical pulses using a temporal optical system. A diffraction grating pair followed by a microwave‐driven, optical phase modulator configured as a time lens is used to uniquely map the pulse shape from the time domain to the frequency domain, allowing measurement of the pulse shape with a spectrometer. We discuss the theory of operation and present experimental results illustrating 3 ps time resolution.
Show PACS
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.30.Kq Fourier optics
07.60.-j Optical instruments and equipment

Band alignment in GaxIn1−xP/InP heterostructures

A. Bensaada, J. T. Graham, J. L. Brebner, A. Chennouf, R. W. Cochrane, R. Leonelli, and R. A. Masut

Appl. Phys. Lett. 64, 273 (1994); http://dx.doi.org/10.1063/1.111178 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
We report low temperature optical absorption measurements on GaxIn1−xP/InP (x<0.2) multiple quantum wells and strained‐layer superlattices. The spectra show several well‐defined peaks whose positions can be fitted within an envelope‐function formalism including strain effects. We deduce conduction band offsets between the larger gap ternary and smaller gap binary materials ranging from 30 to 50 meV. Since these values are intermediate between the strain‐induced shifts for the light‐ and heavy‐hole valence bands, the electrons and heavy holes are localized in the InP layers (type I system), whereas the light holes have their quantum wells in the GaInP layers (type II system).
Show PACS
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.66.Fd III-V semiconductors

Antiresonant reflecting optical waveguides in strip configuration

J. Gehler, A. Bräuer, W. Karthe, and M. Jäger

Appl. Phys. Lett. 64, 276 (1994); http://dx.doi.org/10.1063/1.111179 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
A monomode antiresonant reflecting optical strip waveguide has been realized in SiON. The lateral confinement is provided by strip‐loaded reflectors fabricated by reactive ion beam etching.
Show PACS
42.82.Et Waveguides, couplers, and arrays
42.79.Gn Optical waveguides and couplers

Theory of nonlinear optical absorption in coupled‐band quantum wells with many‐body effects

M. F. Pereira, R. Binder, and S. W. Koch

Appl. Phys. Lett. 64, 279 (1994); http://dx.doi.org/10.1063/1.111180 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
Nonlinear optical absorption spectra and refractive index changes are computed for coupled‐band semiconductor quantum wells by numerically solving the interband polarization equation. The theory combines band‐structure engineering with many‐body techniques and is applied to lattice‐matched GaAs‐AlGaAs and strained InGaAs‐GaAs systems with carrier densities ranging from the excitonic to the gain regimes. Good agreement with recent experimental results is found.
Show PACS
42.65.-k Nonlinear optics
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
78.66.Fd III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Characteristics of 5‐eV absorption band in sputter deposited GeO2‐SiO2 thin glass films

Junji Nishii, Hiroshi Yamanaka, Hideo Hosono, and Hiroshi Kawazoe

Appl. Phys. Lett. 64, 282 (1994); http://dx.doi.org/10.1063/1.111181 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
Thin films (4.6 μm thick) of 5 GeO2‐95 SiO2 and 55 GeO2‐45 SiO2 (mol %) glasses were prepared by rf sputtering method in an Ar‐O2 atmosphere. An intense absorption band at around 5 eV was distinctly observed in both films after the as‐deposited films were annealed at 350 °C for 30 min in a vacuum. A part of this 5‐eV band was gradually decreased by UV irradiation. Saturated absorptivity changes (−Δα∞) of the UV bleached component, which is considered to be the origin of Hill gratings [K. O. Hill, Y. Fujii, and B. S. Kawasaki, Appl. Phys. Lett. 32, 647 (1978)] and second‐harmonic generation in SiO2 glass fibers doped with GeO2, after a prolonged irradiation were 50 cm−1 for 5 GeO2‐95 SiO2 films and 400 cm−1 for 55 GeO2‐45 SiO2 films. These values are greater by one or two orders of magnitude than those (∼2 cm−1) of bulk germanosilicate glasses prepared by the vapor axial deposition method.
Show PACS
42.70.Ce Glasses, quartz
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
81.15.Cd Deposition by sputtering

Generation of electrochemically deposited metal patterns by means of electron beam (nano)lithography of self‐assembled monolayer resists

J. A. M. Sondag‐Huethorst, H. R. J. van Helleputte, and L. G. J. Fokkink

Appl. Phys. Lett. 64, 285 (1994); http://dx.doi.org/10.1063/1.111182 (3 pages) | Cited 29 times

Full Text: | Download PDF

Show Abstract
Submicron metal patterns have been produced by galvanic deposition in openings in a monolayer resist generated by electron beam (e‐beam) lithography. The monolayer resist is a self‐assembled docosanethiol (C22H45SH) layer adsorbed on gold. Proper removal of the thiol requires an e‐beam dose of 10–100 mC cm−2. The positive resist pattern was used to selectively deposit galvanic copper. The size of the Cu patterns is affected by the galvanic deposition time and the CuSO4 concentration in the electrolyte solution. The smallest Cu patterns produced were about 75 nm in width.
Show PACS
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
85.40.Hp Lithography, masks and pattern transfer
81.15.Pq Electrodeposition, electroplating

Direct observation of the etching of damaged surface layers from natural diamond by low‐energy oxygen ion bombardment

T. E. Beerling and C. R. Helms

Appl. Phys. Lett. 64, 288 (1994); http://dx.doi.org/10.1063/1.111183 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
The interaction of oxygen ions with diamond surfaces is reported. Using electron energy loss spectroscopy (EELS), we found that 200 eV oxygen ion bombardment removed surface damaged layers (non‐sp3 bonded), recovering diamond EELS features in the surface region, Higher‐energy oxygen ion bombardment does not produce surfaces as ideal as the 200 eV case. The oxygen surface concentration after the 200 eV oxygen ion irradiation, examined using Auger electron spectroscopy, was determined to be ∼1×1015 cm−2.
Show PACS
81.65.-b Surface treatments
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.80.Jh Ion radiation effects

Band‐gap shift in CdS semiconductor by photoacoustic spectroscopy: Evidence of a cubic to hexagonal lattice transition

O. Zelaya‐Angel, J. J. Alvarado‐Gil, R. Lozada‐Morales, H. Vargas, and A. Ferreira da Silva

Appl. Phys. Lett. 64, 291 (1994); http://dx.doi.org/10.1063/1.111184 (3 pages) | Cited 72 times

Full Text: | Download PDF

Show Abstract
The band‐gap energies of the CdS semiconductor are obtained by a photoacoustic spectroscopy (PAS) technique over a range of temperature of thermal annealing (TTA), in which the evolution of the sample structure is characterized by x‐ray diffraction patterns. The PAS experiment gives a set of data for the band‐gap shift in the region of the fundamental absorption edge. With increasing TTA the band‐gap shift increases up to a critical TTA when its slope decreases in a roughly symmetrical way. It is suggested that at this temperature a cubic to hexagonal‐lattice transition occurs.
Show PACS
71.20.Nr Semiconductor compounds
71.20.Ps Other inorganic compounds
64.70.K- Solid-solid transitions
61.66.Fn Inorganic compounds

Reversible pyroelectric and photogalvanic current in epitaxial Pb(Zr0.52Ti0.48)O3 thin films

J. Lee, S. Esayan, J. Prohaska, and A. Safari

Appl. Phys. Lett. 64, 294 (1994); http://dx.doi.org/10.1063/1.111969 (3 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
The pyroelectric and photogalvanic effects have been studied in epitaxial Pb(Zr0.52Ti0.48)O3 (PZT) thin films. Photoinduced currents, which were completely reversible by electrical voltage, were observed. The photoinduced currents exhibited transient and steady state components. The transient component, in turn, consisted of two components with fast (<1 s) and slow (∼hours) relaxation times. The mechanisms of the photoinduced currents in PZT films and their possible applications in nondestructive readout ferroelectric memory are discussed.
Show PACS
77.70.+a Pyroelectric and electrocaloric effects
77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Oxidation of polycrystalline‐SiGe alloys

H. Tsutsu, W. J. Edwards, D. G. Ast, and T. I. Kamins

Appl. Phys. Lett. 64, 297 (1994); http://dx.doi.org/10.1063/1.111954 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
Polycrystalline‐SiGe (poly‐SiGe) films with Ge concentrations ranging from 5% to 30% were wet oxidized with trichloroethane at temperatures ranging from 700 to 1000 °C. For oxidation temperatures ≥800 °C, the oxidation rate of poly‐SiGe depends only weakly on the Ge concentration. At 700 °C, the oxidation rate increases with Ge concentration and can exceed that at 800 °C. Rutherford backscattering spectra show that, in samples oxidized at or above 800 °C, Ge is completely rejected from the oxide, resulting in a pileup at the interface and diffusion into the poly‐SiGe. At 700 °C, however, Ge is partially incorporated into the growing oxide when layers with high Ge concentration (≥20%) are oxidized. Most of the Ge is still rejected from the oxide and diffuses into the poly‐SiGe layer. This behavior differs from that observed during the oxidation of epitaxial SiGe. Our results can be explained by assuming that diffusion of oxidant through the oxide is the rate controlling step. The oxide composition in turn, depends on the degree with which Ge is rejected from the oxide. The Ge removal rate from the interface exceeds that of single crystal films because of the enhanced diffusion of Ge along grain boundaries.
Show PACS
81.65.-b Surface treatments
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
68.55.-a Thin film structure and morphology

Fluorine ion etching of lead zirconate‐titanate thin films

W. M. Lau, I. Bello, M. Sayer, and Lichun Zou

Appl. Phys. Lett. 64, 300 (1994); http://dx.doi.org/10.1063/1.111185 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The etching reactions of lead zirconate‐titanate (PZT) films with fluorine ions were studied by in situ x‐ray photoelectron spectroscopic (XPS) analysis of the ion bombarded films. The bombardment was carried out with a mass separated low energy ion beam in ultrahigh vacuum and at 30 and 40 eV. It was found that the bombardment at 30 eV and a dose of 1×1017/cm2 (equivalent to 50 monolayers if a surface atom density of 2×1015/cm2 is assumed) at room temperature led to the removal of about 6 nm of PZT. This etch yield is much higher than the expected sputter yield at 30 eV, a phenomenon which clearly indicates the importance of surface chemistry. The XPS data also show that prior to bombardment, a homogeneous oxide was present but that the bombardment induced a surface enrichment of lead and the formation of metal fluorides. Heating the sample to 300 °C in vacuum desorbed virtually all metal fluorides. The results show that reactive ion etching of PZT films with fluorine chemistry is conceivable. However, the reaction mechanism appeared to be very much dependent on the bombardment energy. For example, an increase of the bombardment energy to 40 eV did not only increase the etch yield but also suppressed the surface enrichment of lead and induced the formation of oxy‐fluorides.
Show PACS
81.65.-b Surface treatments
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
82.50.Kx Processes caused by X-rays or γ-rays

Effect of bulk microdefects induced in heat‐treated Czochralski silicon on dielectric breakdown of thermal SiO2 films

Y. Satoh, Y. Murakami, H. Furuya, and T. Shingyouji

Appl. Phys. Lett. 64, 303 (1994); http://dx.doi.org/10.1063/1.111186 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
We examine the effect of bulk microdefects (BMD) intentionally introduced in Czochralski silicon substrates by heat treatment on the dielectric breakdown of thermally grown SiO2 films. Transmission electron microscope observations reveal that the BMD consist of oxygen precipitates, perfect dislocation loops, and faulted dislocation loops. When the BMD are incorporated into the SiO2 film during thermal oxidation, an apparent decrease in the breakdown field is observed. The size of the oxygen precipitates has a clear relationship with the breakdown field: larger oxygen precipitate causes greater degradation. The dislocation loops are unrelated to the breakdown field.
Show PACS
77.22.Jp Dielectric breakdown and space-charge effects
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.Qq Microscopic defects (voids, inclusions, etc.)

AlGaAs/GaAs charge injection transistor/negative resistance field‐effect transistor fabricated with shallow Pd/Ge ohmic contacts

Jiun‐Tsuen Lai and Joseph Ya‐min Lee

Appl. Phys. Lett. 64, 306 (1994); http://dx.doi.org/10.1063/1.111187 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
AlGaAs/GaAs charge injection transistor (CHINT)/negative resistance field‐effect transistor (NERFET) devices are fabricated with Pd/Ge ohmic contacts. Pd and Ge are deposited by e‐beam evaporation. The contact metal layers are annealed by rapid thermal annealing at 450–500 °C for 1 min. This gives a shallow ohmic contact and low specific contact resistivity. The better ρc are on the order of 10−6 Ω cm2. Using Pd/Ge contacts and rapid thermal annealing method, the metallization of CHINT/NERFET becomes much less critical. Good device performance under NERFET mode and CHINT mode is achieved. The largest peak‐to‐valley ratio of NERFET is about 15 at room temperature. The process developed in this work considerably simplifies the fabrication of CHINT/NERFET devices.
Show PACS
85.30.Tv Field effect devices
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.Ht High-field and nonlinear effects

Observation of bias‐induced resonant tunneling peak splitting in a quantum dot

Y. Wang and S. Y. Chou

Appl. Phys. Lett. 64, 309 (1994); http://dx.doi.org/10.1063/1.111188 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
We have observed that, in zero magnetic field, a dc bias across a lateral confined quantum dot (QD) splits each resonant peak in the differential conductance versus the gate voltage measurement into two. The splitting is nearly linear with the applied bias VD. Temperature‐dependence study indicates that the corresponding energy separation between the two splitting peaks is close to eVD. A model is proposed that explains this splitting in terms of the bias‐induced shifting of energy levels in the QD and the splitting of the Fermi level. Using our model, the bias‐induced energy level shift in the QD can be calculated.
Show PACS
73.40.Gk Tunneling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Time dependence of dopant diffusion in δ‐doped Si films and properties of Si point defects

H.‐J. Gossmann, C. S. Rafferty, A. M. Vredenberg, H. S. Luftman, F. C. Unterwald, D. J. Eaglesham, D. C. Jacobson, T. Boone, and J. M. Poate

Appl. Phys. Lett. 64, 312 (1994); http://dx.doi.org/10.1063/1.111189 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
The diffusion of Sb and B in thin Si films grown by low temperature molecular beam epitaxy is investigated in the temperature range 750–900 °C for times of 0.25–60 h. The small spatial extent of the initial δ‐function‐like dopant profiles allows the detection of very small diffusional displacements. The dopant atoms are used as tracers of Si point defects (vacancies and self‐interstitials). Diffusion of Sb is found to be enhanced relative to equilibrium values, while that of B is retarded. We propose a model based on an initial supersaturation of vacancies. Matching this model to the experimental data allows the extraction of the vacancy diffusivity, the activation energy of vacancy formation, and the recombination lifetime of interstitials. The results show that interstitial and vacancy populations cannot be considered independent at low temperature, as has been previously suggested.
Show PACS
66.30.J- Diffusion of impurities
66.30.Lw Diffusion of other defects
61.72.J- Point defects and defect clusters
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Molecular‐beam‐epitaxy growth of GaN on GaAs(100) by using reactive nitrogen source

Z. Q. He, X. M. Ding, X. Y. Hou, and Xun Wang

Appl. Phys. Lett. 64, 315 (1994); http://dx.doi.org/10.1063/1.111190 (3 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
By using a cold cathode ion gun to ionize the nitrogen gas, the molecular‐beam‐epitaxy growth of GaN is carried out. The zinc‐blende structure GaN epilayer grown on the GaAs(100) substrate with a narrow x‐ray diffraction peak width (FWHM) of 23 min and a low carrier concentration of 1017 cm−3 is achieved. The surface optical phonon energies of cubic and hexagonal GaN are experimentally determined to be 82 and 90 meV, respectively.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.Gy Mechanical properties; surface strains

Low resistivity (∼10−5 Ω cm2) ohmic contacts to 6H silicon carbide fabricated using cubic silicon carbide contact layer

V. A. Dmitriev, K. Irvine, M. Spencer, and G. Kelner

Appl. Phys. Lett. 64, 318 (1994); http://dx.doi.org/10.1063/1.111193 (3 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
Silicon carbide is a wide band‐gap semiconductor material which exists in more than 170 polytypes. In this work, heteropolytype epitaxy was used to decrease the specific contact resistance of ohmic contacts to the 6H‐SiC polytype (band gap Eg∼3.0 eV). High quality ohmic contacts were produced by metallizing and annealing a thin cap layer of 3C‐SiC (Eg∼2.3 eV) grown by chemical vapor deposition on either n‐ or p‐type 6H‐SiC. The measured specific contact resistance (rc) of the ohmic contacts to n‐type 6H‐SiC was found to be less than 1.7×10−5 and 2×10−5 Ω cm2 for contacts to p‐type 6H‐SiC.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.40.Cg Contact resistance, contact potential
68.55.-a Thin film structure and morphology

Analysis of normal‐incident absorption in a proposed p‐type very‐narrow‐quantum‐well infrared photodetector

P. Man and D. S. Pan

Appl. Phys. Lett. 64, 321 (1994); http://dx.doi.org/10.1063/1.111194 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
A p‐type very‐narrow‐quantum‐well infrared photodetector is proposed and studied in this letter. Direct transitions between extended‐state heavy‐hole‐like subbands and bound‐state light‐hole‐like subbands are utilized. A first‐principles k⋅p calculation of normal‐incident absorption is performed with no adjustable parameter. Despite quantum wells only 17 Å wide, integrated absorption is found to be stronger in the proposed structure (at T=77 K, from λ=8 μm to λ=10 μm) than in a conventional p‐type quantum‐well infrared photodetector with the same cutoff wavelength. The integrated responsivity is estimated to be more than twice as high, while the integrated shot‐noise‐limited detectivity can be improved by a factor of 2. The proposed structure may also be implemented as a two‐color photodetector.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.66.-w Optical properties of specific thin films

Formation of β‐SiC nanocrystals by the relaxation of Si1−yCy random alloy layers

A. R. Powell, F. K. LeGoues, and S. S. Iyer

Appl. Phys. Lett. 64, 324 (1994); http://dx.doi.org/10.1063/1.111195 (3 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
In this work we consider the relaxation behavior of Si1−yCy random alloys grown epitaxially on Si, with 0.005≳y≳0.05. The Si1−yCy layers are under tensile strain as grown and at annealing temperatures below 900 °C the relaxation of strain is achieved by dislocation formation, in a fashion similar to SiGe relaxation. However, at temperatures in excess of 900 °C the C, which at lower temperatures remained in substitutional sites, precipitates out of the lattice, this removes all of the tensile strain from the layer. The nature of this precipitation is to form single crystal, nanoparticles of β‐SiC with the same lattice orientation as the Si lattice in which they are created. These nanoparticles are of uniform diameter (3±1 nm for y=0.005 Si1−yCy material) and randomly dispersed throughout the original Si1−yCy region. This ability to produce nanocrystals of wide band‐gap material within the Si matrix should enable the exploration of mesoscopic phenomena. The nanoparticles once formed also block the movement of dislocations, thus locking in any strain fields associated with the dislocations.
Show PACS
81.30.Mh Solid-phase precipitation
68.60.Dv Thermal stability; thermal effects
68.55.-a Thin film structure and morphology

Thermal budget consideration in rapid isothermal processing

R. P. S. Thakur and R. Singh

Appl. Phys. Lett. 64, 327 (1994); http://dx.doi.org/10.1063/1.111165 (3 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Rapid isothermal processing (RIP) based on incoherent radiation as the source of thermal and optical energy is emerging as a key low‐thermal budget processing technique. Because of high heating and cooling rates, the RIP cycle generally refers to processing time and temperature. In this letter, we have shown that the properties of materials and devices fabricated by RIP depends on the heating and cooling rates. Optimized heating and cooling rates can minimize unwanted phenomena (e.g., higher thermal stress, warpage, etc.) leading to the improved performance of the devices fabricated by RIP. To demonstrate this significance of heating and cooling rates, we report the wafer dimensional analysis results for ramp rates of 15, 75, 100, 150, and 200 °C per second at a maximum steady‐state temperature of 1050 °C. Plasma and low‐pressure chemical vapor deposition silicon nitride films on 6‐in. wafers were studied for warpage. The BF2 and As implanted wafers at a fixed dose of 8×1015/cm2 were studied for slow (15 °C per second) and fast (200 °C per second) ramp rates. We also present stress, secondary ion mass spectroscopy, and diode leakage current results for different RIP cycles of interest.
Show PACS
85.40.Hp Lithography, masks and pattern transfer
81.65.-b Surface treatments
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Franz–Keldysh effect in a two‐dimensional system

A. Schmeller, W. Hansen, J. P. Kotthaus, G. Tränkle, and G. Weimann

Appl. Phys. Lett. 64, 330 (1994); http://dx.doi.org/10.1063/1.111166 (3 pages) | Cited 23 times

Full Text: | Download PDF

Show Abstract
We report luminescence and photocurrent experiments on an InGaAs/GaAs quantum well in strong lateral electric fields. The fields are imposed with an interdigitated gate on the crystal surface that consists of an array of metal stripes with a 250 nm period. The small period allows generation of electric fields of about 105 V/cm by application of only 1.5 V at the gate electrodes. Strong subgap absorption and oscillations of the interband absorption as function of radiation energy are observed and discussed in view of the Franz–Keldysh effect. The resulting photo‐I‐V characteristic shows high potential for electro‐optic applications.
Show PACS
78.66.Fd III-V semiconductors
72.40.+w Photoconduction and photovoltaic effects
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Fivefold multiply twinned crystallites in CuInSe2

Takahiro Wada, Takayuki Negami, and Mikihiko Nishitani

Appl. Phys. Lett. 64, 333 (1994); http://dx.doi.org/10.1063/1.111167 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
The microstructure of polycrystalline CuInSe2 thin films are studied by cross‐sectional high resolution electron microscopy. The CuInSe2 films were deposited on a Mo coated glass substrate by three‐source evaporation. The film contained fivefold multiply twinned crystallites as well as a high density of twins in {112} planes. The formation of these defects are discussed.
Show PACS
61.72.Mm Grain and twin boundaries
68.55.-a Thin film structure and morphology
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close