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

20 Jun 1994

Volume 64, Issue 25, pp. 3365-3511

Page 1 of 2 Pages Next Page | Jump to Page

Doubly resonant second harmonic generation of 2.0 μm light in coupled InGaAs/AlAs quantum wells

H. C. Chui, E. L. Martinet, G. L. Woods, M. M. Fejer, J. S. Harris, C. A. Rella, B. I. Richman, and H. A. Schwettman

Appl. Phys. Lett. 64, 3365 (1994); http://dx.doi.org/10.1063/1.111276 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
We demonstrate intersubband absorption and second harmonic generation (SHG) in asymmetric coupled In0.6Ga0.4As/AlAs n‐type quantum wells (QWs) grown on a GaAs substrate. Intersubband absorption at 4.1 and 2.1 μm wavelengths, corresponding to the 1 to 2 and 1 to 3 transitions, respectively, are observed. SHG of 2.0 μm light is demonstrated in this doubly resonant QW. This is the shortest wavelength SHG to date in any n‐type QW system. The second order nonlinear susceptibility χ(2) is measured using a free electron laser by interference of the second harmonic fields from the QW and substrate. At a pump wavelength of 4.0 μm, a large asymmetry in the SHG power with rotation angle of the sample arising from SHG from the QW is observed, and a χ(2) of magnitude 20±8 nm/V, approximately 100 times that of bulk GaAs, and phase 63°±34° relative to the GaAs substrate is measured. Comparison of both the linear and nonlinear properties to a simple model is discussed.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.66.Fd III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Accurate fabrication of anamorphic microlenses and efficient collimation of tapered unstable‐resonator diode lasers

Z. L. Liau, J. N. Walpole, D. E. Mull, C. L. Dennis, and L. J. Missaggia

Appl. Phys. Lett. 64, 3368 (1994); http://dx.doi.org/10.1063/1.111277 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
Highly precise f/0.9 refractive anamorphic microlenses have been fabricated in GaP substrates by mass‐transport smoothing of etched multiple‐mesa structures. Astigmatic outputs from tapered unstable‐resonator lasers have been collimated to a nearly round beam of near diffraction‐limited 0.43° divergence. Initial good efficiencies (as high as 35%) have been obtained in coupling the laser output into a single‐mode fiber. These lenses are highly promising for realizing simple compact optical systems that exploit the high power capability of tapered lasers.
Show PACS
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.79.Bh Lenses, prisms and mirrors
42.55.Px Semiconductor lasers; laser diodes
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Thermally stable polyester polymers for second‐order nonlinear optics

Ajay Nahata, Chengjiu Wu, Charles Knapp, Victor Lu, J. Shan, and James T. Yardley

Appl. Phys. Lett. 64, 3371 (1994); http://dx.doi.org/10.1063/1.111278 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We report electro‐optic and thermal stability properties of a novel thermostable fluorene‐based polyester polymer. The electro‐optic coefficient, r33, at 810 nm is 2.6 pm/V for a poling field of 0.5 MV/cm. This value is comparable to that obtained from many reported side‐chain polymers. Isothermal decay measurements of the charge transfer absorption band and electro‐optic effect demonstrate that the chemical stability of the fluorene molecule appears to dominate over orientational relaxation in the decline of the electro‐optic response at elevated temperatures.
Show PACS
42.70.Jk Polymers and organics
78.20.Jq Electro-optical effects
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Restoration of dual‐frequency signals with nonlinear propagation in fibers with positive group velocity dispersion

P. V. Mamyshev, P. G. Wigley, J. Wilson, C. Bosshard, and G. I. Stegeman

Appl. Phys. Lett. 64, 3374 (1994); http://dx.doi.org/10.1063/1.111279 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
It is shown experimentally and theoretically that a sinusoidally modulated pulse evolves with time into a train of dark soliton‐like pulses and then returns to its initial sinusoidal shape on propagation through a nonlinear single‐mode fiber with positive group velocity dispersion. The experimental results are in agreement with predictions from the nonlinear Schrödinger equation.
Show PACS
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.81.-i Fiber optics

Temporal and spatial evolution of laser ablated plasma from YBa2Cu3O7

S. S. Harilal, P. Radhakrishnan, V. P. N. Nampoori, and C. P. G. Vallabhan

Appl. Phys. Lett. 64, 3377 (1994); http://dx.doi.org/10.1063/1.111280 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
YBa2Cu3O7 target was laser ablated, and the time‐of‐flight (TOF) distributions of Y, Y+, and YO in the resultant plasma were investigated as functions of distance from the target and laser energy density using emission spectroscopy. Up to a short distance from the target (≂1.5 cm), TOF distributions show twin peaks for Y and YO, while only single‐peak distribution is observed for Y+. At greater distances (≳1.5 cm) all of them exhibit single‐peak distribution. The twin peaks are assigned to species corresponding to those generated directly/in the vicinity of target surface and to those generated from collisional/recombination process.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
78.47.-p Spectroscopy of solid state dynamics
52.25.-b Plasma properties
74.72.-h Cuprate superconductors

Improvement of the lasing performance of the CuCl‐He laser by adding Ag atoms as energy donors and Cs atoms as energy acceptors

Yuuki Masumura, Toshiaki Ishikawa, Hiroshi Saitoh, Masamichi Ishibashi, and Kan‐ichi Fujii

Appl. Phys. Lett. 64, 3380 (1994); http://dx.doi.org/10.1063/1.111281 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The lasing performance of the CuCl‐He system has been largely improved with increases in the pulse widths and pulse peak values by adding Ag atoms as energy donors and Cs atoms as energy acceptors. As typical results, we simultaneously obtained a range from 20 to 40 ns of the pulse widths and an average increase in the peak power of the laser pulses from 103 to 288 W. Our experimental equipment was a homemade small size simple laser device.
Show PACS
42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.By Design of specific laser systems
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Generation of high repetition rate far‐infrared laser pulses

E. R. Mueller, T. E. Wilson, J. Waldman, J. T. Kennedy, and R. A. Hart

Appl. Phys. Lett. 64, 3383 (1994); http://dx.doi.org/10.1063/1.111282 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
We report the generation of pulsed optically pumped far‐infrared (FIR) radiation with a repetition rate of 200 kHz. These pulses were obtained in a straightforward method by pumping a FIR resonator with a high repetition rate, rf‐excited, waveguide CO2 laser. Pulses approximately 50 ns wide were generated both at 432.6 μm in HCOOH, and 117.7 μm in CH2F2. The pulse width of the FIR radiation was studied as a function of the CO2 pulse width, and the relative delay between the two was measured. Based on this data we conclude that the FIR radiation was gain switched and of a duration which was a function of either the gain bandwidth of the FIR transition, or more likely the FIR cavity parameters.
Show PACS
84.30.Ng Oscillators, pulse generators, and function generators
42.72.Ai Infrared sources

Sm:YAG optical pressure sensor to 180 GPa:Calibration and structural disorder

Jun Liu and Yogesh K. Vohra

Appl. Phys. Lett. 64, 3386 (1994); http://dx.doi.org/10.1063/1.111283 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
We report ultrahigh pressure calibration and fluorescence intensity measurements of Sm:YAG to 180 GPa in a diamond anvil cell at room temperature. Several fluorescence emission bands excited by argon ion laser were followed with increasing pressure and it was observed that Y4 band was the most intense in the pressure regime of 100–180 GPa. The Y4 band is calibrated against the R band of ruby to 180 GPa. Irreversible changes in the line intensities above 100 GPa were observed in Sm:YAG and quenched to ambient pressure. Linewidths of the fluorescence bands of the quenched phase indicate structural disorder. In contrast to ruby pressure sensor, the Y4 emission band of Sm:YAG is easily detectable at ultrahigh pressures.
Show PACS
62.50.-p High-pressure effects in solids and liquids
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
78.55.Hx Other solid inorganic materials
06.20.F- Units and standards

Study and analysis of submicron‐period grating formation on polymers ablated using a KrF laser irradiated phase mask

P. E. Dyer, R. J. Farley, R. Giedl, C. Ragdale, and D. Reid

Appl. Phys. Lett. 64, 3389 (1994); http://dx.doi.org/10.1063/1.111284 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
Submicron‐period gratings have been formed in polyethylene terephthalate and polyimide films using a KrF laser irradiated, zero suppressed, phase mask with a period d=533 nm. The imprinted grating has a dominant period of d rather than d/2, a result which is shown to be due to recording the pattern by a threshold surface ablation process.
Show PACS
42.70.Jk Polymers and organics
79.20.Ds Laser-beam impact phenomena

Effects of the interface bonding type on the optical and structural properties of InAs‐AlSb quantum wells

Berinder Brar, James Ibbetson, Herbert Kroemer, and John H. English

Appl. Phys. Lett. 64, 3392 (1994); http://dx.doi.org/10.1063/1.111285 (3 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
InAs‐AlSb short period superlattices were grown with both InSb‐like or AlAs‐like interfaces and their properties were studied using photoluminescence, x‐ray diffraction, and transmission electron microscopy. A shift of 96 meV in the photoluminescence peak position is observed, with the peak from the sample with InSb‐like interfaces being at a lower energy. The shift is interpreted as an interface band structure effect. X‐ray diffraction patterns indicate that the sample with InSb‐like interfaces grows pseudomorphically to the AlSb buffer layer, while the sample with AlAs‐like interfaces is heavily dislocated. Transmission electron micrographs confirm the x‐ray data.
Show PACS
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors

Photopumped long wavelength vertical‐cavity surface‐emitting lasers using strain‐compensated multiple quantum wells

C. H. Lin, C. L. Chua, Z. H. Zhu, F. E. Ejeckam, T. C. Wu, Y. H. Lo, and R. Bhat

Appl. Phys. Lett. 64, 3395 (1994); http://dx.doi.org/10.1063/1.111286 (3 pages) | Cited 11 times

Full Text: | Download PDF


See Also: Erratum

Show Abstract
We report optically pumped long wavelength vertical‐cavity surface‐emitting lasers (VCSELs) made of strain‐compensated multiple quantum wells. The structure of the VCSELs consists of 30 pairs of compressive strained wells and tensile strained barriers as the gain medium and Si/SiO2 dielectric mirrors. The lasers operate at 1.59 μm wavelength. The threshold power density was measured to be 3 kW/cm2 at room temperature, corresponding to a threshold current density of about 2 kA/cm2. The VCSELs have a characteristic temperature T0 of 90 K between 10 and 60 °C, and 60 K from 70 to 110 °C.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
68.55.-a Thin film structure and morphology

Pulse‐time‐modulated electron cyclotron resonance plasma etching for highly selective, highly anisotropic, and notch‐free polycrystalline silicon patterning

Seiji Samukawa

Appl. Phys. Lett. 64, 3398 (1994); http://dx.doi.org/10.1063/1.111290 (3 pages) | Cited 37 times

Full Text: | Download PDF

Show Abstract
Highly selective, highly anisotropic, and notch‐free etching for polycrystalline silicon is achieved in a few tens of μs pulse‐time‐modulated electron cyclotron resonance plasma. In the pulsed plasma, the selectivity ratio of polycrystalline silicon etching rate to the SiO2 etching rate is drastically improved with high etching rate, as compared with the ratio with a continuous discharge. Furthermore, vertical and notch‐free phosphorus‐doped polycrystalline silicon etching profiles can be achieved even with 100% over etching. These etching characteristics are achieved by controlling ion energy distributions through the duty ratio, maintaining a high ion current density, generating a collimated ion flux and eliminating surface charging with a pulsed discharge of a few tens of μs.
Show PACS
85.40.Hp Lithography, masks and pattern transfer
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
52.75.-d Plasma devices
52.50.Dg Plasma sources

Running waveguide discharge for inner coating of metal tubes

R. Hytry, W. Möller, and R. Wilhelm

Appl. Phys. Lett. 64, 3401 (1994); http://dx.doi.org/10.1063/1.111291 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
A plasma‐enhanced chemical vapor deposition process by means of the so‐called running discharge has been developed. Amorphous hydrogenated carbon (C:H) films were deposited over a length of 2.5 m on the inner wall of an assembled waveguide system. The average deposition rate from a running discharge in methane was 0.27 Å/s. An increase of the average deposition rate to 2.6 Å/s was achieved using acetylene as process gas, while the H/C ratio in the C:H films remains nearly constant at one. The breakdown of a discharge in the metallic waveguide has been studied in argon plasmas depending on magnetic field, microwave power, and gas pressure. A sharp transition between a magnetically enhanced localized discharge and a running discharge was observed at increasing pressure in the range of some Pascal at a microwave power of 100 W. The running velocity (∼104 m/s) of the plasma package increases with increasing microwave power and increasing gas pressure. This plasma behavior has been further investigated by means of the power balance and plasma modeling in methane.
Show PACS
52.80.Pi High-frequency and RF discharges
52.50.Gj Plasma heating by particle beams
52.40.Hf Plasma-material interactions; boundary layer effects

Copper patterning on dielectrics by laser writing in liquid solution

L. Minì, C. Giaconia, and C. Arnone

Appl. Phys. Lett. 64, 3404 (1994); http://dx.doi.org/10.1063/1.111292 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
A technique suitable for laser induced deposition of copper on LiNbO3 and glass is presented. Deposition is achieved from Cu salt solution mixed with glycerol, after coating the surface with a very thin metal film. High resolution and low electrical resistivity can be achieved, using laser power levels in the 20‐mW range. The technique can be used for electrode and interconnect fabrication in integrated optical devices, as well as mask repair or microelectronics applications.
Show PACS
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
82.50.-m Photochemistry
85.40.Ls Metallization, contacts, interconnects; device isolation

Microstructure of epitaxial oxide thin film heterostructures on silicon by pulsed laser deposition

Subodh G. Ghonge, Edward Goo, R. Ramesh, R. Haakenaasen, and D. K. Fork

Appl. Phys. Lett. 64, 3407 (1994); http://dx.doi.org/10.1063/1.111293 (3 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
The microstructure of epitaxial La0.5Sr0.5CoO3(LSCO)/ferroelectric lanthanum modified lead zirconate titanate (PLZT)/ La0.5Sr0.5CoO3(LSCO)/bismuth titanate(BT)/yttria‐stabilized zirconia (YSZ) heterostructures on [001] silicon has been investigated. X‐ray diffraction and pole figure analysis reveal epitaxial growth of the PLZT, LSCO, BT, and YSZ layers. High resolution transmission electron microscopy was done to study the crystal defects and interfacial structure.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
81.15.Np Solid phase epitaxy; growth from solid phases
68.35.B- Structure of clean surfaces (and surface reconstruction)

Structure of Au ultrafine particles in silica glass: X‐ray diffraction study

Kohei Fukumi, Akiyoshi Chayahara, Masaki Makihara, Kanenaga Fujii, Junji Hayakawa, and Mamoru Satou

Appl. Phys. Lett. 64, 3410 (1994); http://dx.doi.org/10.1063/1.111296 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Structure of ultrafine gold particles embedded in silica glass has been studied by the x‐ray diffraction method. It is found that the gold particles have an effective temperature factor of 1.84 Å−2 and include a few layers of plane faults. It is deduced that the gold particles in silica glass are highly defective owing to the mismatch of the thermal expansion coefficient.
Show PACS
61.66.-f Structure of specific crystalline solids
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
81.05.Kf Glasses (including metallic glasses)

Pulsed laser deposition of silicon carbide at room temperature

M. A. Capano, S. D. Walck, P. T. Murray, D. Dempsey, and J. T. Grant

Appl. Phys. Lett. 64, 3413 (1994); http://dx.doi.org/10.1063/1.111257 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
The objective of this letter is to report on the successful deposition of SiC by pulsed laser deposition at room temperature. Deposition of SiC films is accomplished by ablating a 6H‐SiC target, using the 248 nm radiation from a KrF∗ excimer laser. X‐ray photoelectron spectroscopy data conclusively show that the films are silicon carbide. The Si 2p peaks are observed from a film at 100.3 eV, from a 6H‐SiC standard at 100.3 eV, and from a Si standard at 99.7 eV. Similar scans of the C 1s peak reveal a shift in binding energy from 284.7 eV for a graphite standard, to 283.3 eV for a deposited film, and 283.4 eV for the SiC standard. Further, the integrated areas and shapes of the peaks from the film and the SiC standard are equivalent. Transmission electron microscopy reveals a film microstructure which is largely amorphous, but which contains a significant volume fraction of SiC crystallites. Analysis of the electron diffraction patterns indicates that the crystallites are β‐SiC. The relationship between the film microstructure and the energy contained within the laser‐generated plume is also considered.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.55.-a Thin film structure and morphology

Giant capacitance oscillations related to the quantum capacitance in GaAs/AlAs superlattices

Yaohui Zhang, Yuexia Li, Desheng Jiang, Xiaoping Yang, and Penghua Zhang

Appl. Phys. Lett. 64, 3416 (1994); http://dx.doi.org/10.1063/1.111258 (3 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
We have observed periodic current and capacitance oscillations with increasing bias on doped GaAs/AlAs superlattices at a temperature of 77 K. The maximum of the observed capacitance is larger than usual geometric capacitances in superlattices, being comparable to the quantum capacitance of the two‐dimensional (2D) electron system proposed by Luryi. A model based on well‐to‐well sequential resonant tunneling due to the movement of the boundary between the electric field domains in superlattice was proposed to explain the origin of the giant capacitance oscillations. It was demonstrated that the capacitance at the peaks of capacitance‐voltage (C‐V) characteristics reflects the quantum capacitance of the space‐charge region at the boundary between the domains (a novel 2D electron system).
Show PACS
73.40.Gk Tunneling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.50.Dn Low-field transport and mobility; piezoresistance

Suppression of Cu diffusion from a bulk ZnSe substrate to a homoepitaxial layer by Se‐beam irradiation as a pregrowth treatment

Yuji Hishida, Tadao Toda, Tomoyuki Yoshie, Katsumi Yagi, Takao Yamaguchi, and Tatsuhiko Niina

Appl. Phys. Lett. 64, 3419 (1994); http://dx.doi.org/10.1063/1.111259 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Cu diffusion of homoepitaxial ZnSe was investigated through low‐temperature photoluminescence (PL) spectra and secondary ion mass spectroscopy. Though Cu in ZnSe normally diffuses easily, we found that Cu in a ZnSe substrate did not diffuse into the homoepitaxial layer when the substrate was heated under Se‐beam irradiation prior to growth. Cu‐related emissions, such as Ideep1 and Cu‐green, disappeared from the PL spectrum of the homoepitaxial layer grown on the Se‐beam irradiated substrate. This suppressed Cu diffusion can be explained by site transformation of interstitial Cu atoms in the ZnSe substrate into Cu atoms occupying the Zn lattice site. This treatment is very useful for improving the purity of homoepitaxial ZnSe layers.
Show PACS
61.72.J- Point defects and defect clusters
66.30.J- Diffusion of impurities
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Et II-VI semiconductors

Semiconducting polymer diodes: Large size, low cost photodetectors with excellent visible‐ultraviolet sensitivity

G. Yu, K. Pakbaz, and A. J. Heeger

Appl. Phys. Lett. 64, 3422 (1994); http://dx.doi.org/10.1063/1.111260 (3 pages) | Cited 135 times

Full Text: | Download PDF

Show Abstract
Photodiodes fabricated from conjugated polymers exhibit excellent sensitivity to visible‐UV radiation. The photosensitivity increases with reverse bias voltage. The photoresponse of diodes fabricated from poly(3‐octyl thiophene) is relatively flat in the visible and near UV; for wavelengths shorter than 550 nm, the absolute sensitivity is greater than 0.3 A/W under reverse bias of 15 V, larger than that of commercial UV‐enhanced Si photodiodes. Photodiodes made from poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene], MEH‐PPV, sensitized with C60, show similar sensitivity. The ease of fabrication into large size, arbitrary shapes, and even onto flexible substrates makes the polymer photodiode a novel photodetector with potential for use in a wide range of applications.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.79.Pw Imaging detectors and sensors

S2Cl2 treatment: A new sulfur passivation method of GaAs surface

Z. S. Li, W. Z. Cai, R. Z. Su, G. S. Dong, D. M. Huang, X. M. Ding, X. Y. Hou, and Xun Wang

Appl. Phys. Lett. 64, 3425 (1994); http://dx.doi.org/10.1063/1.111261 (3 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
We have developed a new sulfur passivation method—S2Cl2 treatment, which is quite effective for removing the surface oxide layer of GaAs and passivating the surface with monolayer thick sulfides. Photoluminescence (PL) spectroscopy, Auger electron spectroscopy (AES), and x‐ray photoelectron spectroscopy (XPS) are used to study the passivated GaAs (100) surfaces. The results of PL reveal that the PL intensity increases by two orders of magnitude, which is indicative of the reduction of surface recombination velocity of GaAs by this treatment. AES data prove that the sulfurized surface contains S, Ga, As, C, and small amount of Cl atoms but no oxygen signal at all. XPS study shows that sulfur atoms bond to both Ga and As atoms more effectively on S2Cl2 treated surfaces than those passivated by (NH4)2Sx.
Show PACS
73.20.At Surface states, band structure, electron density of states
73.90.+f Other topics in electronic structure and electrical properties of surfaces, interfaces, thin films, and low-dimensional structures (Restricted to new topics in section 73)
81.10.Dn Growth from solutions

Effects of wafer bow and warpage on the integrity of thin gate oxides

R. P. S. Thakur, N. Chhabra, and A. Ditali

Appl. Phys. Lett. 64, 3428 (1994); http://dx.doi.org/10.1063/1.111231 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
We have studied the effects of initial wafer bow and warpage on the integrity of thinner gate oxides grown by both furnace and rapid thermal processing (RTP) methods. There is evidence of a correlation between wafer warpage and bow to the charge‐to‐breakdown characteristics of the gate oxide. An almost linear increase in defect density was observed when plotted as a function of increasing wafer warpage. The lifetime (t50%) of the samples with initial warpage of 10 μm or less is reported higher than those with initial warpage of more than 60 μm for both furnace and RTP‐grown oxides. The value of bow for the warped samples was taken for cases with the highest positive and negative values so both kinds of shape trends could be investigated. With initial wafer warpage ranging from 4 to 70 μm, we present the results of wafer dimensional analysis and correlate these to defect density and lifetime studies for thin gate oxides.  
Show PACS
77.55.-g Dielectric thin films
73.20.Hb Impurity and defect levels; energy states of adsorbed species
85.30.Tv Field effect devices
85.30.Fg Bulk semiconductor and conductivity oscillation devices (including Hall effect devices, space-charge-limited devices, and Gunn effect devices)

High performance InGaAs/GaAs quantum well infrared photodetectors

S. D. Gunapala, K. M. S. V. Bandara, B. F. Levine, G. Sarusi, J. S. Park, T. L. Lin, W. T. Pike, and J. K. Liu

Appl. Phys. Lett. 64, 3431 (1994); http://dx.doi.org/10.1063/1.111232 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
We have measured the optical and transport properties of In0.2Ga0.8As/GaAs quantum well infrared photodetectors based on bound‐to‐bound, bound‐to‐quasibound, and bound‐to‐continuum intersubband transitions. Excellent hot electron transport and high detectivity D∗=1.8×1010 cm√Hz/W (at λp=16.7 μm) were achieved at temperature T=40 K.
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
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Relation between hole density and impurity density in ZnMgSSe semiconductors

K. Kondo, H. Okuyama, and A. Ishibashi

Appl. Phys. Lett. 64, 3434 (1994); http://dx.doi.org/10.1063/1.111233 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
Using amphoteric native defect model [Walukiewicz, Phys. Rev. B 37, 4760 (1988)], we have considered the energy‐gap Eg dependence of nitrogen doping in ZnMgSSe semiconductors. We have explained the energy‐gap Eg dependence of saturated hole concentration in ZnMgSSe semiconductors based on the amphoteric native defect model and available effective hole masses in ZnSe using the valence band discontinuity ΔEv as a fitting parameter. The Fermi‐level stabilization energy EFS and the pinned Fermi‐level energy ESI are, to a good approximation, universal for II‐VI materials as well as for III‐V materials. We have estimated the ESI is located at 1.895 eV below EFS. It is indicated that the band‐gap discontinuity between ZnSe and ZnMgSSe is ΔEc: ΔEv=0.55:0.45 if effective hole mass is 1.4 m0 for ZnMgSSe and ΔEc:ΔEv=0.67:0.33 if effective hole mass is 0.6 m0.  
Show PACS
61.72.S- Impurities in crystals

Field electron emission from hydrogenated amorphous silicon films on tungsten: Light‐induced effects

D. S. Joag, A. K. Sharma, M. A. More, R. O. Dusane, and M. G. Takwale

Appl. Phys. Lett. 64, 3437 (1994); http://dx.doi.org/10.1063/1.111234 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Field electron emission from a hydrogenated amorphous silicon deposited tungsten tip has been studied. The effect of prolonged (hourly) exposure to light on the field electron emission current has been investigated. The current‐voltage characteristics of the as‐deposited, light exposed, and annealed states of the emitter showed semiconducting behavior in accordance with the Fowler–Nordheim law. In case of an initially annealed emitter tip, the field emission current was found to increase monotonically with the light exposure, reversibly for shorter durations of a few minutes. The effect of long term (hourly) exposure of light resulted in the increase in the field emission current level nonlinearly with the exposure time. The current level did not come down to the original level even after switching off the light in contrast to the effect of short duration light exposure. The enhancement in the field emission current has been attributed to tunneling though the dangling bond states created by light exposure. The results have been discussed in light of the Staebler–Wronski effect.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
73.61.Cw Elemental semiconductors
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close