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

2 Dec 1996

Volume 69, Issue 23, pp. 3453-3607

Page 1 of 3 Pages Next Page | Jump to Page

Experimental characterization of reactive ion etched germanium diffraction gratings at 10.6 μm

J. Stiens, W. Ranson, R. Cottam, C. De Tandt, R. Vounckx, V. Kotov, G. Shkerdin, B. Dhoedt, and R. Baets

Appl. Phys. Lett. 69, 3453 (1996); http://dx.doi.org/10.1063/1.117249 (3 pages)

Full Text: | Download PDF

Show Abstract
An experimental study of diffraction gratings reactive ion etched in germanium is performed. Gratings are designed for the 10.6 μm infrared CO2 laser. Different etchants have been compared to pattern 3‐μm‐deep grooves in the germanium layers evaporated on a GaAs substrate. The experimental diffraction efficiency (maximum 30%) of the prototype gratings are in good accordance with the theoretical predictions. The U‐shaped grooves have still to be further optimized. © 1996 American Institute of Physics.
Show PACS
42.70.Km Infrared transmitting materials
42.79.Dj Gratings
81.65.Cf Surface cleaning, etching, patterning
81.05.Cy Elemental semiconductors

Photoluminescence related to the two‐dimensional electron gas at a GaN/AlGaN heterointerface

J. P. Bergman, T. Lundström, B. Monemar, H. Amano, and I. Akasaki

Appl. Phys. Lett. 69, 3456 (1996); http://dx.doi.org/10.1063/1.117250 (3 pages) | Cited 33 times

Full Text: | Download PDF

Show Abstract
We report photoluminescence (PL) spectra related to a two‐dimensional electron gas confined at a GaN/AlGaN heterointerface. The recombination between electrons confined in the bottom of the interface potential and photoexcited holes causes a broad PL emission about 50 meV below the GaN exciton emissions. A second emission, attributed to the recombination of electrons in the first excited level at the interface, is also observed close to the excitonic band gap in GaN. The data agree with a self‐consistent calculation of the energy levels and electron concentration at the interface. © 1996 American Institute of Physics.
Show PACS
78.55.Cr III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics
73.20.At Surface states, band structure, electron density of states

The effect of scaling microlasers on modal noise

S. M. K. Thiyagarajan and A. F. J. Levi

Appl. Phys. Lett. 69, 3459 (1996); http://dx.doi.org/10.1063/1.117251 (3 pages)

Full Text: | Download PDF

Show Abstract
Modal noise and speckle visibility in Gb/s multimode fiber interconnect systems depends on a complex interplay of carrier dynamics, spontaneous emission factor, gain compression, and device dimensions. These competing factors allow scaled low‐power microlasers with optimized design and operating conditions to exhibit modal noise comparable to large incoherent multimode devices. © 1996 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers
42.60.Mi Dynamical laser instabilities; noisy laser behavior
78.45.+h Stimulated emission

Observations of two separable photoquenching phenomena in lightly n‐type bulk GaAs by optical absorption, Hall effect, and positron annihilation

S. Tüzemen, C. Le Berre, C. Corbel, M. R. Brozel, and M. Yildirim

Appl. Phys. Lett. 69, 3462 (1996); http://dx.doi.org/10.1063/1.117252 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
We show that two different types of photoquenching effect take place under low temperature illumination of lightly n‐type bulk GaAs. Both phenomena result in an increase in positron trapping at vacancies. The first associated with a decrease in EL2 absorption, is produced with light of 1.1 μm wavelength and recovers near 100 K. While little photoquenching related to EL2 is observed after illumination close to the band edge (0.83 μm), persistent increases in Hall voltage and positron lifetime accompanied by a decrease in near band‐edge absorption are observed. These latter phenomena recover at 50 K. © 1996 American Institute of Physics.
Show PACS
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
78.30.Fs III-V and II-VI semiconductors
78.70.Bj Positron annihilation

Vacuum field induced mixing of light and heavy‐hole excitons in a semiconductor microcavity

E. Goobar, R. J. Ram, J. Ko, G. Björk, M. Oestreich, and A. Imamoglu

Appl. Phys. Lett. 69, 3465 (1996); http://dx.doi.org/10.1063/1.117253 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Measurements in a semiconductor microcavity reveal the coupling between light‐ and heavy‐hole excitons that is mediated by the electromagnetic vacuum. Three polariton modes constructed from superpositions of heavy‐hole excitons, light‐hole excitons, and photons are observed. The experimental results are in good agreement with the theory of three‐coupled bosonic modes, each coupled to an independent reservoir. © 1996 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers
71.35.Gg Exciton-mediated interactions
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
42.50.-p Quantum optics

Form birefringence of volume gratings in photopolymers

Changxi Yang and Pochi Yeh

Appl. Phys. Lett. 69, 3468 (1996); http://dx.doi.org/10.1063/1.117254 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We investigate experimentally the form birefringence due to photoinduced one‐ and two‐dimensional volume index gratings in DuPont photopolymers. Experimental results on the dispersion of the form birefringence versus the illumination wavelength and the grating period for one‐dimensional gratings are presented. We also investigate the form birefringence due to two‐dimensional volume gratings. Positive form birefringence and biaxial form birefringence can be obtained by recording two volume gratings with different grating wave vectors. © 1996 American Institute of Physics.
Show PACS
42.79.Dj Gratings
42.70.Ln Holographic recording materials; optical storage media
42.70.Jk Polymers and organics
78.20.Fm Birefringence

Near field scanning optical microscopy measurements of optical intensity distributions in semiconductor channel waveguides

C. D. Poweleit, David H. Naghski, Susan M. Lindsay, Joseph T. Boyd, and Howard E. Jackson

Appl. Phys. Lett. 69, 3471 (1996); http://dx.doi.org/10.1063/1.117255 (3 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
We present results of near field scanning optical microscopy measurements performed on single mode AlGaAs ridge channel waveguides. The optical intensity distribution just above the surface of the waveguide structure has been measured by scanning a tapered, aluminum‐coated, fiber probe transverse to the waveguide propagation direction. Experimental results are compared with model calculations performed using both the effective index and beam propagation methods. An accurate description of submicron features in the intensity profile near the ridge edges, as well as the magnitude of the field outside the channel, requires the use of the beam propagation method. © 1996 American Institute of Physics.
Show PACS
42.79.Gn Optical waveguides and couplers
07.79.Fc Near-field scanning optical microscopes

Wide bandwidth (100) GaAs/fluorides quarter‐wavelength Bragg reflectors grown by molecular beam epitaxy

Z. Shi, H. Zogg, P. Müller, I. D. Jung, and U. Keller

Appl. Phys. Lett. 69, 3474 (1996); http://dx.doi.org/10.1063/1.117256 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Broadband quarter‐wavelength Bragg reflectors that consist of periodic stacks of fluorides (CaF2–BaF2–CaF2) and GaAs, centered at 1.4 μm, were grown by molecular beam epitaxy. Despite a total fluoride thickness as high as 720 nm, crack‐free surface morphology was obtained. In this letter, we report a crack‐free standard quarter‐wavelength III–V semiconductor‐fluoride Bragg reflector. With only three stacks, the bandwidth with reflectance above 95% is about 650 nm (1.15–1.80 μm), while, near the center wavelength, the reflectivity is as high as 99%. Both important wavelengths of 1.3 and 1.55 μm for optical communication are included in the very wide high reflectance plateau. These mirrors are expected to have wide applications for optical and optoelectronic devices. © 1996 American Institute of Physics.
Show PACS
42.79.Fm Reflectors, beam splitters, and deflectors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.66.Fd III-V semiconductors
78.66.Nk Insulators

Ring and stripe oxide‐confined vertical‐cavity surface‐emitting lasers

D. L. Huffaker, H. Deng, Q. Deng, and D. G. Deppe

Appl. Phys. Lett. 69, 3477 (1996); http://dx.doi.org/10.1063/1.117257 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
Ring and stripe oxide‐confined vertical‐cavity surface‐emitting lasers are studied. Interesting coupling effects are observed due to the nonzero propagation velocity of the optical mode in the plane of the cavity. The stripe geometries appear interesting due to the very low threshold and provide a convenient means for increasing the aperture size while maintaining uniform current pumping. The ring laser provides a means of obtaining well defined multiple spots in the far field. © 1996 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Transient photoconductivity in quantum well infrared photodetectors

M. Ershov

Appl. Phys. Lett. 69, 3480 (1996); http://dx.doi.org/10.1063/1.117258 (3 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
Transient photoconductivity in quantum well infrared photodetectors (QWIPs) is studied using numerical modeling. Transient photocurrent in QWIPs illuminated by steplike infrared radiation consists of two components. A fast component, representing the primary photocurrent, is determined by the processes of the carrier capture to the QWs and transit through the QW structure. Its amplitude can be lower than the steady‐state photocurrent due to the sweep‐out of the photoexcited carriers. A slow component, comprising the multiplied photocurrent, is governed by the recharging of the QWs. The QWIPs can exhibit high photocurrent gain only at frequencies of harmonic infrared radiation lower than the inverse characteristic time of establishing equilibrium at the injecting contact. © 1996 American Institute of Physics.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Bt Optoelectronic device characterization, design, and modeling
73.50.Pz Photoconduction and photovoltaic effects

Enhancement of the acoustic phase conjugate reflectivity in nonlinear piezoelectric ceramics by applying static electric or static stress fields

M. Ohno and K. Takagi

Appl. Phys. Lett. 69, 3483 (1996); http://dx.doi.org/10.1063/1.117259 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
A method to enhance the reflectivity of acoustic phase conjugate mirrors by nonlinear piezoelectricity is discussed. Static electric or static stress fields were applied together with the pump electric field. In highly nonlinear piezoelectric ceramics, the phase conjugate reflectivity was enhanced by the factor of 50 using this method. The maximum reflectivity reached 10−2. © 1996 American Institute of Physics.
Show PACS
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
43.25.Dc Nonlinear acoustics of solids
62.65.+k Acoustical properties of solids

Elastic guided waves in plates with rough surfaces

O. I. Lobkis and D. E. Chimenti

Appl. Phys. Lett. 69, 3486 (1996); http://dx.doi.org/10.1063/1.117260 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
In this letter we report experimental measurements and calculations of elastic wave propagation and dispersion in a waveguide with randomly rough surfaces, as a model of incipient corrosion. Experiments are performed in fluid immersion on a smooth aluminum plate and on one with 26‐μm rms roughness, determined by independent acoustic profilometry. The calculation exploits the phase‐screen approximation as the basis for a transverse‐resonance derivation of the frequency/velocity dispersion relation in an elastic waveguide with rough surfaces. Comparisons of frequency spectra for two propagation lengths show good agreement between model and experiment. © 1996 American Institute of Physics.
Show PACS
43.20.Gp Reflection, refraction, diffraction, interference, and scattering of elastic and poroelastic waves
43.35.Zc Use of ultrasonics in nondestructive testing, industrial processes, and industrial products
62.30.+d Mechanical and elastic waves; vibrations
81.70.Cv Nondestructive testing: ultrasonic testing, photoacoustic testing

Synthesis of crystalline carbon nitride thin films by laser processing at a liquid–solid interface

A. K. Sharma, P. Ayyub, M. S. Multani, K. P. Adhi, S. B. Ogale, M. Sunderaraman, D. D. Upadhyay, and S. Banerjee

Appl. Phys. Lett. 69, 3489 (1996); http://dx.doi.org/10.1063/1.117261 (3 pages) | Cited 26 times

Full Text: | Download PDF

Show Abstract
Pulsed laser induced reactive quenching at a liquid–solid interface was used for the synthesis of tetrahedrally coordinated crystalline carbon nitride on a tungsten substrate. The crystalline phase was identified by transmission electron diffraction. X‐ray photoelectron spectroscopy indicated that the carbon atoms are coordinated only tetrahedrally with nitrogen—as expected for C3N4. The atomic percentage of N (considering only those atoms coordinated with C) is about 35%. © 1996 American Institute of Physics.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.55.Nq Composition and phase identification
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

Manipulation of growth modes in heteroepitaxy: Ni/Cu(111)

Wulf Wulfhekel, Ingo Beckmann, Nuphar N. Lipkin, Georg Rosenfeld, Bene Poelsema, and George Comsa

Appl. Phys. Lett. 69, 3492 (1996); http://dx.doi.org/10.1063/1.117222 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
Growth manipulation methods, which have been successfully used to improve the growth of homoepitaxial films, are applied to molecular beam epitaxy of the heteroepitaxial system Ni/Cu(111). The procedures applied are temperature reduction during nucleation and pulsed ion bombardment during deposition. While the first does not lead to smoother films, the ion beam assisted growth is successful in reducing the film roughness. © 1996 American Institute of Physics.
Show PACS
81.15.Jj Ion and electron beam-assisted deposition; ion plating
81.05.Bx Metals, semimetals, and alloys
61.05.Np Atom, molecule, and ion scattering (for structure determination only)
68.35.Fx Diffusion; interface formation

High electron mobility in bipolar composites of organic molecules

L.‐B. Lin, S. A. Jenekhe, and P. M. Borsenberger

Appl. Phys. Lett. 69, 3495 (1996); http://dx.doi.org/10.1063/1.117223 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
Electron and hole mobilities in bipolar molecular composites of N,N′‐bis(1,2‐dimethyl‐ propyl)‐1,4,5,8‐naphthalenetetracarboxylic diimide (NTDI) and tri‐p‐tolylamine (TTA) are reported. The electron mobility in NTDI/TTA composites is found to be enhanced by factors of 4 to 6 compared to pure NTDI. These results demonstrate a new approach to improving electron mobility in organic materials. © 1996 American Institute of Physics.
Show PACS
73.50.Pz Photoconduction and photovoltaic effects
73.61.Ph Polymers; organic compounds
72.40.+w Photoconduction and photovoltaic effects
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Control of Co flux through ternary compound for the formation of epitaxial CoSi2 using Co/Ti/Si system

Gi Bum Kim, Hong Koo Baik, and Sung Man Lee

Appl. Phys. Lett. 69, 3498 (1996); http://dx.doi.org/10.1063/1.117224 (3 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
A ternary compound of Co3Ti2Si is suggested as reaction barrier for the formation of epitaxial CoSi2 in the Co/Ti/Si system. It has a role to control Co diffusion to the Si substrate, followed by formation of CoSi2. After Co3Ti2Si was formed, CoO and Ti oxide were formed at surface, depending on Ti thickness. In the case of Ti oxide being at surface, the outdiffusion of Ti in ternary compound was accelerated. Then, the decomposition of Co3Ti2Si occurred by reaction with Ti oxide, resulting in uniform epitaxial CoSi2. However, in the case of CoO being at surface, the Ti outdiffusion was suppressed, followed by thermally decomposition of Co3Ti2Si. This caused nonuniform Co supply to form nonuniform CoSi2. © 1996 American Institute of Physics.
Show PACS
66.30.Ny Chemical interdiffusion; diffusion barriers
68.60.Dv Thermal stability; thermal effects
68.35.Fx Diffusion; interface formation

Structural and mechanical properties of (B0.5−xSix)N0.5 films synthesized by dual‐ion‐beam deposition

C. W. Ong, X.‐A. Zhao, Y. M. Ng, K. F. Chan, T. C. Tsang, C. L. Choy, and P. W. Chan

Appl. Phys. Lett. 69, 3501 (1996); http://dx.doi.org/10.1063/1.117225 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The structural and mechanical properties of ion‐beam deposited (B0.5−xSix)N0.5 films (0≤x≤0.5) were characterized by x‐ray photoelectron spectroscopy, infrared absorption experiments, and nanoindentation tests. A single‐layer BN film (x=0) has 70 vol. % in cubic phase (c‐BN), and a hardness of 38 GPa. However, it peeled off very soon after deposition due to the high internal stress. If a buffer layer was deposited first, followed by a (B0.5−xSix)N0.5 film with x≊0.013, the whole configuration adhered very firmly to both quartz and silicon substrates. This improvement in adhesion was probably due to the formation of Si–N bonds, which served to release partly the stress inside the (B0.5−xSix)N0.5 films. Since the Si content was low, the film structure remained highly cubic, and there was no observable drop in hardness. For higher x, the cubic structure in (B0.5−xSix)N0.5 films disappeared rapidly and was replaced by a hexagonal structure. This structural change led to a rapid drop in hardness from 38 to 12 GPa. As x was further increased, more Si–N bonds were formed in the (B0.5−xSix)N0.5 layers. As a result, the hardness increased from the minimum value to a value ≊24 GPa. © 1996 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties
81.15.Jj Ion and electron beam-assisted deposition; ion plating

Local electron field emission characteristics of pulsed laser deposited diamondlike carbon films

F. Y. Chuang, C. Y. Sun, T. T. Chen, and I. N. Lin

Appl. Phys. Lett. 69, 3504 (1996); http://dx.doi.org/10.1063/1.117226 (3 pages) | Cited 28 times

Full Text: | Download PDF

Show Abstract
Local electron field emission properties of diamondlike carbon (DLC) films were measured by a probe method in 1 atmosphere ambient pressure, using the modified scanning tunneling microscopic (STM) system, and the diode method. In the STM probe method, the field emission was turn on at a low bias as +2.67 V. A large emission current of 40 nA was attained at +7 volt bias voltage and the emission current density was estimated as Jt=5 A/cm2. By contrast, the current–voltage (I–V) characteristics of the same DLC films measured by diode method in 10−6 Torr ambient pressure revealed that the electron field emission was produced for a 13.2 V/μm electric field, and a high emission current density of J=160 μA/cm2 was obtained for a E=20 V/μm electric field. The geometrical enhancement factor (α), evaluated from the Fowler–Nordheim plot was around α=30, which is larger than what would be expected from a planar surface. This can be interpreted as the evidence that electrons are emitted locally from spherical SP3 clusters. © 1996 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
81.15.Fg Pulsed laser ablation deposition
81.05.ub Fullerenes and related materials

Evidence of the role of positive bias in diamond growth by hot filament chemical vapor deposition

Jingbiao Cui and Rongchuan Fang

Appl. Phys. Lett. 69, 3507 (1996); http://dx.doi.org/10.1063/1.117227 (3 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
Diamond films have been deposited on a positively biased silicon substrate by hot filament chemical vapor deposition. It is found that the size distribution of the diamond particle is uniform under bias conditions. The effects of the bias on reactive gas composition were investigated by in situ infrared absorption and in situ optical emission with Ar actinometry. These techniques indicate that the bias does not significantly influence the gas composition. Diamond growth under bias conditions for a small region masked by metal Mo is similar to that without bias. These results confirm that the influence of bias on diamond growth is caused by electron and/or negative ion bombardment on the surface of the substrate and the growing crystallites rather than by the change in gaseous environments. © 1996 American Institute of Physics.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.ub Fullerenes and related materials

Comparison of electrical and luminescence data for the A center in CdTe

A. Castaldini, A. Cavallini, B. Fraboni, P. Fernandez, and J. Piqueras

Appl. Phys. Lett. 69, 3510 (1996); http://dx.doi.org/10.1063/1.117228 (3 pages) | Cited 26 times

Full Text: | Download PDF

Show Abstract
We have investigated the electrical and optical properties of the deep levels responsible for the 1.4–1.5 eV luminescence band usually observed in II–VI compounds. We compared the energy levels found by cathodoluminescence and junction spectroscopy methods for semi‐insulating (CdTe:Cl and Cd0.8Zn0.2Te) and semiconducting samples (undoped CdTe). The techniques utilized were deep level transient spectroscopy (DLTS) on semiconducting samples and photoinduced current transient spectroscopy and photo‐DLTS on high resistivity materials. These last two techniques are complementary and allow the determination of the trap character (donor/acceptor). Three acceptor levels are seen in the electrical transient data at Ev+0.12, 0.14, and 0.16 eV with hole capture cross sections of 2×10−16, 1×10−16, and 4×10−17 cm2, respectively. The lowest level is seen only in Cl doped material corroborating the literature optical and electron spin resonance identification of a level at Ev+0.12 eV as being a VCd+ClTe donor–acceptor pair center. All three levels may be present in the 1.4 eV luminescence band. © 1996 American Institute of Physics.
Show PACS
71.55.Gs II-VI semiconductors
78.60.Hk Cathodoluminescence, ionoluminescence
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)

Effect of thermal annealing on optical emission properties of low‐temperature grown AlGaAs/GaAs multiple quantum wells

W. Feng, F. Chen, W. X. Wang, W. Q. Cheng, Y. Yu, Q. Huang, and J. M. Zhou

Appl. Phys. Lett. 69, 3513 (1996); http://dx.doi.org/10.1063/1.117229 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
We have investigated the effect of thermal annealing on optical emission properties of low‐temperature (LT) grown AlGaAs/GaAs multiple quantum wells (MQWs) by using photoluminescence (PL) spectroscopy. For comparison, the results on normal‐temperature (NT) grown MQWs implanted with protons are also presented. The LT sample was grown by molecular beam epitaxy at 310 °C. The as‐grown LT‐MQWs show moderately strong PL. Upon annealing at 600 °C, the PL intensity of the LT‐MQWs is dramatically quenched, in sharp contrast to the large increase in PL intensity of the implanted NT‐MQWs. The quenching of PL intensity in the LT‐MQWs is attributed to the formation of arsenic clusters that fast trap photoexcited carriers. In addition, an enhancement in the interface intermixing and roughening induced by thermal annealing has also been observed in the LT‐MQWs. © 1996 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

High‐reliability blue‐shifted InGaAsP/InP lasers

J.‐P. Noël, D. Melville, T. Jones, F. R. Shepherd, C. J. Miner, N. Puetz, K. Fox, P. J. Poole, Y. Feng, E. S. Koteles, S. Charbonneau, R. D. Goldberg, and I. V. Mitchell

Appl. Phys. Lett. 69, 3516 (1996); http://dx.doi.org/10.1063/1.117230 (3 pages) | Cited 20 times

Full Text: | Download PDF

Show Abstract
InGaAsP/InP quantum well (QW) ridge waveguide lasers emitting nominally at 1310 nm have been ‘‘blue‐shifted’’ selectively (as much as 70 nm) on a full 50‐mm‐diameter wafer after growth. P+ ion implantation at 1 MeV, 200 °C through a variable thickness SiO2 mask was used to induce various degrees of QW intermixing after postimplantation annealing at 700 °C. Irrespective of the amount of intermixing induced (blue shift), all fabricated devices exhibited 20–25 mA lasing threshold current and 0.25–0.30 W/A differential quantum efficiency. Device reliability was equivalent to standard (nonimplanted) lasers when the wavelength shift was 35 nm or less, corresponding to predicted lifetime in excess of 25 years while operating cw at 25 °C. The performance and reliability data clearly indicate that the concentration of residual defects introduced in the active region by the implantation/annealing process is negligibly small. The present results, which are a product of a straightforward fabrication process, suggest the possibility of manufacturing high‐reliability, low‐cost, monolithically integrated optoelectronic chips containing, for example, selectively tuned lasers, optical amplifiers, modulators, and waveguides. © 1996 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
78.66.Fd III-V semiconductors
61.72.uj III-V and II-VI semiconductors

A near‐field scanning optical microscopy study of the photoluminescence from GaN films

Jutong Liu, N. R. Perkins, M. N. Horton, J. M. Redwing, M. A. Tischler, and T. F. Kuech

Appl. Phys. Lett. 69, 3519 (1996); http://dx.doi.org/10.1063/1.117231 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
We have achieved spatially resolved photoluminescence from GaN films using a near‐field scanning optical microscope (NSOM). GaN films grown by hydride vapor phase epitaxy (HVPE) and metal‐organic vapor phase epitaxy (MOVPE) on sapphire substrates have been studied. We have performed spatial scans of topography, band edge, and yellow luminescence signals. Atomic force microscopy measurements were also made and compared with the NSOM topography. We have found spatial variations in photoluminescence characteristics at the submicron scale for both HVPE and MOVPE GaN. The observed enhancement of yellow luminescence at multiatomic step edges on the HVPE GaN surface suggests that the yellow luminescence is associated with chemical impurities incorporated during the growth of GaN films. © 1996 American Institute of Physics.
Show PACS
07.79.Fc Near-field scanning optical microscopes
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
81.05.Ea III-V semiconductors

Far‐infrared emission from parabolically graded quantum wells

K. D. Maranowski, A. C. Gossard, K. Unterrainer, and E. Gornik

Appl. Phys. Lett. 69, 3522 (1996); http://dx.doi.org/10.1063/1.117232 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
We have observed grating coupled far infrared (FIR) emission from parabolically graded quantum wells (PQWs) by the application of an in‐plane electric field. The peak emission frequency from different wells matches the designed harmonic oscillator frequency for each well, as determined by the curvature of the PQWs. This is a confirmation that the generalized Kohn theorem applies for emission of FIR radiation. © 1996 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
78.66.Fd III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Vacuum ultraviolet reflectivity measurements of thin‐film electroluminescent phosphors

K. Lite, R. L. Thuemler, T. K. Plant, J. F. Wager, D. C. Morton, S. S. Sun, and R. H. Mauch

Appl. Phys. Lett. 69, 3525 (1996); http://dx.doi.org/10.1063/1.117233 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Vacuum ultraviolet reflectivity measurements of three thin‐film electroluminescent phosphors, zinc sulfide (ZnS), strontium sulfide (SrS), and strontium‐calcium thiogallate (Sr0.45Ca0.55Ga2S4), are reported using thin‐film samples. Measured ZnS reflectivity peak positions are in agreement with values previously reported in the literature. SrS room temperature reflectivity measurements are found to be consistent with previously reported low temperature measurements. Reflectivity measurements of Sr0.45Ca0.55Ga2S4 are reported for the first time; the reflectivity spectrum is found to rise monotonically above the band gap and to exhibit almost no structure, except for a small shoulder at ∼6.8 eV and a single, broad peak at ∼8.5 eV. The unusual nature of the Sr0.45Ca0.55Ga2S4 reflectivity spectrum is attributed to positional disorder in the stoichiometric thiogallate film. © 1996 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
78.66.Hf II-VI semiconductors
78.40.Fy Semiconductors
Page 1 of 3 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close