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

18 Mar 1996

Volume 68, Issue 12, pp. 1595-1735

Page 1 of 2 Pages Next Page | Jump to Page

Partial screening of internal electric fields in strained piezoelectric quantum well lasers: Implications for optoelectronic integration

A. S. Pabla, J. Woodhead, E. A. Khoo, R. Grey, J. P. R. David, and G. J. Rees

Appl. Phys. Lett. 68, 1595 (1996); http://dx.doi.org/10.1063/1.115662 (3 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
The spectral electroluminescence characteristics of broad‐area (Al)GaAs/In0.23Ga0.77As/(Al)GaAs single quantum well separate confinement heterostructure lasers grown on (111)B GaAs have been studied under forward biased current injection. A room‐temperature threshold current density of 750 A/cm2 is measured for a 1000 μm laser. The subthreshold electroluminescence spectrum blue shifts with increasing current up to the point of lasing threshold. Our measurements reveal that lasing is achieved while there is a strong residual or ‘‘unscreened’’ electric field across the quantum well. Based on these observations we outline how piezoelectric quantum wells can be used to monolithically integrate a quantum well laser with a blue‐shifting electroabsorption modulator. © 1996 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
78.60.Fi Electroluminescence

Effect of facet roughness on etched‐facet semiconductor laser diodes

D. A. Francis, C. J. Chang‐Hasnain, and K. Eason

Appl. Phys. Lett. 68, 1598 (1996); http://dx.doi.org/10.1063/1.115663 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
We calculate the effects of facet roughness on laser performance of etched‐facet semiconductor diode lasers. Facet roughness can be caused by the finite pixel size, used in photolithographic mask fabrication, or in the facet etching process. We consider various sizes of roughness and show that appreciable effects can result from roughness levels previously considered optically flat. Far‐field shifts and modal coupling caused by facet roughness are also calculated. Results are highly useful for designing lasers with curved or arbitrarily oriented facts such as unstable resonators or beam steering fan laser diodes. © 1996 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.82.Cr Fabrication techniques; lithography, pattern transfer

Optoelectronic feedback stabilization of current modulated laser diodes

Jaume Dellunde and M. C. Torrent

Appl. Phys. Lett. 68, 1601 (1996); http://dx.doi.org/10.1063/1.115664 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Optoelectronic feedback is proposed as a suitable method for output stabilization of current modulated laser diodes. Numerical simulations show low jitter operation with significant on/off ratios even beyond the relaxation oscillation frequency. Low frequency components in the output power spectra are efficiently suppressed. © 1996 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Fc Modulation, tuning, and mode locking

Ultrafast electro‐optic field sensors

Q. Wu and X.‐C. Zhang

Appl. Phys. Lett. 68, 1604 (1996); http://dx.doi.org/10.1063/1.115665 (3 pages) | Cited 167 times

Full Text: | Download PDF

Show Abstract
We report our recent study of ultrafast electro‐optic field sensors for the coherent measurement of freely propagating subpicosecond pulsed electromagnetic waves (THz beams). The sensitivity and bandwidth of these electro‐optic sensors are comparable with the conventional ultrafast photoconductive dipole antennas. The simplicity of the detection geometry and capability of optical parallel processing make these sensors suitable for real‐time 2D subpicosecond far‐infrared imaging. © 1996 American Institute of Physics.
Show PACS
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.79.Pw Imaging detectors and sensors
78.20.Jq Electro-optical effects

A normal force distance regulation scheme for near‐field optical microscopy

R. J. Stephenson and M. E. Welland

Appl. Phys. Lett. 68, 1607 (1996); http://dx.doi.org/10.1063/1.115666 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
A near‐field optical microscope (NFOM) has been developed that combines the features of a near‐field optical microscope and an atomic force microscope. Improved control over tip‐sample separation has led to improved optical imaging and independent surface topography information. The tip oscillation is normal to the sample plane thereby reducing lateral forces—important for nonperturbative imaging of soft samples. Both topographic images and reflection near‐field optical images are presented which demonstrate the capability of the system. © 1996 American Institute of Physics.
Show PACS
07.79.Fc Near-field scanning optical microscopes
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

Nonlinear self‐phase matching of optical second harmonic generation in lithium niobate

Sergei Orlov, Amnon Yariv, and Mordechai Segev

Appl. Phys. Lett. 68, 1610 (1996); http://dx.doi.org/10.1063/1.115667 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
We show that the nonlinear index perturbation due to light‐induced photovoltaic space‐charge field in LiNbO3 can give rise to self‐phase matching of second harmonic generation. Increase of the conversion efficiency is accompanied by formation of stationary and nonstationary patterns in the spatial structure of the generated second harmonic. The space‐charge field can be induced either by the initially non‐phase‐matched second harmonic or by an external seed. © 1996 American Institute of Physics.
Show PACS
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Optical characterization of waveguide based photonic microstructures

Thomas F. Krauss and Richard M. De La Rue

Appl. Phys. Lett. 68, 1613 (1996); http://dx.doi.org/10.1063/1.115668 (3 pages) | Cited 42 times

Full Text: | Download PDF

Show Abstract
Third‐order, one‐dimensional, semiconductor‐air gratings have been designed, fabricated, and evaluated by optical waveguide transmission measurements. Gratings with as little as six unit cells show a clear band edge around 840–850 nm. Owing to our approach of semiconductor‐rich lattices with small airgaps, the diffractive spreading loss is sufficiently small (∼50% in the passband) for meaningful results to be extracted. The measurements indicate that the optical waveguide approach is a good starting point for the study of photonic microstructures and that practical device concepts can be implemented. © 1996 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials

Direct observation of ultraviolet laser induced photocurrent in oxygen deficient silica and germanosilicate glasses

Victor N. Bagratashvili, Svetlana I. Tsypina, Pavel V. Chernov, Aleksey O. Rybaltovskii, Yuriy S. Zavorotny, Sergey S. Alimpiev, Yaroslav O. Simanovskii, Liang Dong, and Philip St. J. Russel

Appl. Phys. Lett. 68, 1616 (1996); http://dx.doi.org/10.1063/1.115669 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
UV laser induced inonization of silicon oxygen deficient centers (SODC) in silica glasses and germanium oxygen deficient centers (GODC) in germanosilicate glasses has been studied by direct displacement photocurrent measurements. For both SODC and GODC the two‐photon (two‐step) nature of photoionization has been established. The cross sections of transitions from first excited to upper (ionizable) states were estimated as σ12=6×10−18 cm2 for SODC and (0.5–1.0)×10−19 cm2 for GODC. The effect of pulse‐to‐pulse degradation of the photocurrent signal caused by the screening effect is applied to estimate the lifetimes and ranges of the free carriers. The conclusion was drawn, that ionized SODC and GODC play the key role for free charge trapping. © 1996 American Institute of Physics.
Show PACS
78.66.Jg Amorphous semiconductors; glasses
82.50.Bc Processes caused by infrared radiation
82.50.Hp Processes caused by visible and UV light

Symmetric rate model for fluorocarbon plasma etching of SiO2

Ji Ding and Noah Hershkowitz

Appl. Phys. Lett. 68, 1619 (1996); http://dx.doi.org/10.1063/1.115670 (3 pages) | Cited 27 times

Full Text: | Download PDF

Show Abstract
A symmetric rate model for plasma etching and plasma deposition in fluorocarbon plasmas is proposed. When there is no deposition, the symmetric rate model gives a plasma etch rate. When there is no etching, the model gives a plasma deposition rate. Electron cyclotron resonance and reactive ion etcher etch rates of SiO2 in CF4 plasma are found to be consistent with the model. © 1996 American Institute of Physics.
Show PACS
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Completely passivated high conductivity copper films made by annealing Cu/Al bilayers

Wei Wang, W. A. Lanford, and S. P. Murarka

Appl. Phys. Lett. 68, 1622 (1996); http://dx.doi.org/10.1063/1.115671 (3 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Thin films made by annealing Cu(500 nm)/Al(7 nm)/SiO2/Si are investigated using Rutherford backscattering and resistivity measurements. Annealing these films in a low pressure of oxygen results in the formation of a thin surface layer of hole‐free aluminum oxide which protects the underlying copper from oxidation. Even when heated in air at 350 °C for 4 h, no growth of copper oxide is detected. These films have a resistivity as low as 2.4 μΩ cm, comparable to the resistivity of pure copper films (2.1 μΩ cm) made in the same deposition system. The use of such films for microelectronic metallization is briefly discussed. © 1996 American Institute of Physics.
Show PACS
81.65.-b Surface treatments
85.40.Ls Metallization, contacts, interconnects; device isolation

Cu segregation at the Al(Cu)/Al2O3 interface

M. Copel, K. P. Rodbell, and R. M. Tromp

Appl. Phys. Lett. 68, 1625 (1996); http://dx.doi.org/10.1063/1.115672 (3 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
We have investigated the segregational properties of polycrystalline Al(Cu) alloys in the composition range of 0.04 to 0.5 at. % Cu using medium energy ion scattering. While Cu does not segregate to the bare surface, significant quantities of Cu are found at the interface between the Al(Cu) and aluminum oxide. By measuring the interfacial Cu concentration as a function of temperature, we have determined that the segregational energy is 0.21±0.03 eV. © 1996 American Institute of Physics.
Show PACS
61.72.S- Impurities in crystals
64.75.-g Phase equilibria
66.30.Qa Electromigration
68.35.Fx Diffusion; interface formation

Coexistence of incommensurate antiferroelectric and relaxorlike ferroelectric orderings in high Zr‐content La‐modified lead zirconate titanate ceramics

Z. Xu, Xunhu Dai, Jie‐Fang Li, and Dwight Viehland

Appl. Phys. Lett. 68, 1628 (1996); http://dx.doi.org/10.1063/1.115673 (3 pages) | Cited 19 times

Full Text: | Download PDF

Show Abstract
Lanthanum modified lead zirconate titanate (PLZT) ceramics with a Zr/Ti ratio of 85/15 were investigated as a function of La content by dielectric spectroscopy, Sawyer–Tower polarization techniques, and electron microscopy. Tweedlike structures were found to evolve from normal μm‐sized ferroelectric domains with increasing La content above 4 at. %. For a composition with 6 at. % La, an incommensurate antiferroelectric state was found to coexist with a polar nanodomain state, where the size of the nanodomains was approximately equal to the value of the incommensurate modulation wavelength. For this composition, P–E studies revealed double hysteresis characteristics, whereas dielectric investigations revealed relaxorlike ferroelectric behavior. © 1996 American Institute of Physics.
Show PACS
77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Band‐A emission in synthetic diamond films: A systematic investigation

Marco Marinelli, A. Hatta, T. Ito, A. Hiraki, and T. Nishino

Appl. Phys. Lett. 68, 1631 (1996); http://dx.doi.org/10.1063/1.115674 (3 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
Several sets of diamond films were grown by microwave plasma enhanced chemical vapor deposition (CVD) using a CH4–H2 gas mixture. The growth conditions were systematically changed in order to obtain different film morphologies, preferential orientations, and crystal qualities. In particular, the substrate temperature Ts and the CH4 concentration in the gas mixture were varied in the ranges 850–950 °C and 0.4%–2.0%, respectively. The resulting films were characterized by x‐ray diffraction, Raman spectroscopy, and scanning electron microscopy. Room‐temperature cathodoluminescence has been investigated in the energy range 1.55–6.20 eV (200–800 nm). A clear correlation of the 2.85 eV (435 nm) emission band, the so‐called band A, with both the substrate temperature and CH4 content in the gas mixture during deposition, was observed. An explanation is given in terms of crystal defects and diamond film texturing induced by the growth process. © 1996 American Institute of Physics.
Show PACS
61.72.J- Point defects and defect clusters
78.60.Hk Cathodoluminescence, ionoluminescence
81.05.Cy Elemental semiconductors

Initial stages in the growth of carbon films produced in an Ar–CH4–H2 microwave discharge: Composition and surface layers morphology

L. Thomas, I. Jauberteau, J. L. Jauberteau, M. J. Cinelli, J. Aubreton, and A. Catherinot

Appl. Phys. Lett. 68, 1634 (1996); http://dx.doi.org/10.1063/1.115675 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
X‐ray photoelectron spectroscopy and atomic force microscopy are employed in the characterization of the first stages in the growth of carbon layers on a (001) Si substrate which is not scratched with diamond powder before placing it in an Ar–2%CH4–H2 plasma discharge. Results show that the first layers could be formed in SiC grains where the carbon diamond particles nucleate. The high nucleation density of 1.109–5.109 nuclei. cm−2 and the low aggregates density lead to a smooth surface. © 1996 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Formation of ultralow friction surface films on boron carbide

A. Erdemir, C. Bindal, and G. R. Fenske

Appl. Phys. Lett. 68, 1637 (1996); http://dx.doi.org/10.1063/1.115676 (3 pages) | Cited 41 times

Full Text: | Download PDF

Show Abstract
In this letter, we describe the formation and ultralow friction mechanisms of a surface film on boron carbide (B4C). This film results from sequential reactions between B4C and oxygen and between the resulting boron oxide (B2O3) and moisture; it can afford friction coefficients of 0.03 to 0.05 to sliding steel surfaces. At temperatures above 600 °C, B4C undergoes oxidation and forms a layer of boron oxide (B2O3) in the upper surface. During cooling to room temperature, the B2O3 reacts with moisture in the air to form a secondary film, boric acid (H3BO3). The sliding friction coefficient of 440C steel balls against this film is 0.04, compared to 0.7 against the bare B4C surfaces. Mechanistically, we propose that the ultralow friction behavior of the heat‐treated B4C surface is due mainly to the layered‐crystal structure of the H3BO3 film that forms on the sliding surface. © 1996 American Institute of Physics.
Show PACS
68.35.Gy Mechanical properties; surface strains
81.65.-b Surface treatments

Characterization of nanocrystalline diamond films by core‐level photoabsorption

D. M. Gruen, A. R. Krauss, C. D. Zuiker, R. Csencsits, L. J. Terminello, J. A. Carlisle, I. Jimenez, D. G. J. Sutherland, D. K. Shuh, W. Tong, and F. J. Himpsel

Appl. Phys. Lett. 68, 1640 (1996); http://dx.doi.org/10.1063/1.115677 (3 pages) | Cited 75 times

Full Text: | Download PDF

Show Abstract
Core‐level photoabsorption has been used to determine the sp2 and sp3 bonding content of nanocrystalline diamond thin films grown using C60 or CH4 precursors. The C(1s) absorption spectra show clear bulk diamond excitonic and sp3 features with little evidence of sp2 bonding, while the Raman spectra measured from these same films are ambiguous and indeterminate. This result can be attributed to the local structure (near‐neighbor bonding) sensitivity of core‐level photoabsorption that is insensitive to domain size, unlike Raman spectroscopy. © 1996 American Institute of Physics.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
78.30.-j Infrared and Raman spectra
68.55.Nq Composition and phase identification
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Thermal stability of amorphous carbon films grown by pulsed laser deposition

T. A. Friedmann, K. F. McCarty, J. C. Barbour, M. P. Siegal, and Dean C. Dibble

Appl. Phys. Lett. 68, 1643 (1996); http://dx.doi.org/10.1063/1.115891 (3 pages) | Cited 62 times

Full Text: | Download PDF

Show Abstract
The thermal stability in vacuum of amorphous tetrahedrally coordinated carbon (a‐tC) films grown on Si has been assessed by in situ Raman spectroscopy. Films were grown in vacuum on room‐temperature substrates using laser fluences of 12, 22, and 45 J/cm2 and in a background gas of either hydrogen or nitrogen using a laser fluence of 45 J/cm2. The films grown in vacuum at high fluence (≳20J/cm2) show little change in the a‐tC Raman spectra with temperature up to 800 °C. Above this temperature the films convert to glassy carbon (nanocrystalline graphite). Samples grown in vacuum at lower fluence or in a background gas (H2 or N2) at high fluence are not nearly as stable. For all samples, the Raman signal from the Si substrate (observed through the a‐tC film) decreases in intensity with annealing temperature indicating that the transparency of the a‐tC films is decreasing with temperature. These changes in transparency begin at much lower temperatures (∼200 °C) than the changes in the a‐tC Raman band shape and indicate that subtle changes are occurring in the a‐tC films at lower temperatures. © 1996 American Institute of Physics.
Show PACS
68.60.Dv Thermal stability; thermal effects

Stable electroluminescence from reverse biased n‐type porous silicon–aluminum Schottky junction device

S. Lazarouk, P. Jaguiro, S. Katsouba, G. Masini, S. La Monica, G. Maiello, and A. Ferrari

Appl. Phys. Lett. 68, 1646 (1996); http://dx.doi.org/10.1063/1.115892 (3 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
We report the realization of a bright and stable electroluminescent Schottky diode based on aluminum‐porous silicon junction. White light, visible in normal daylight, is emitted when a reverse bias is applied to the device, promoting the junction breakdown. The device has a fast (100 ns) rise time of the light emission. An excellent stability, tested over more than one month of continuous operation at a high bias level, is achieved by the complete encapsulation of the active porous silicon under a transparent alumina layer. The external power efficiency of light emission is 0.01%. © 1996 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
85.60.Jb Light-emitting devices

On the origin of the 1.5 μm luminescence in ion beam synthesized β‐FeSi2

D. N. Leong, M. A. Harry, K. J. Reeson, and K. P. Homewood

Appl. Phys. Lett. 68, 1649 (1996); http://dx.doi.org/10.1063/1.115893 (2 pages) | Cited 36 times

Full Text: | Download PDF

Show Abstract
In this letter we present photoluminescence results on β‐FeSi2/Si using excitation energies above and below the silicon band gap. These results show that the luminescence emission observed at 1.5 μm can be firmly attributed to band edge related emission from the β‐FeSi2. This result confirms the potential of β‐FeSi2 as a strong contender for a silicon compatible optoelectronics technology that matches the conventional optical fiber transmission wavelength at 1.5 μm. © 1996 American Institute of Physics.
Show PACS
78.55.Hx Other solid inorganic materials
78.66.Li Other semiconductors

Tunable and adaptive bandpass filter using a nonlinear dielectric thin film of SrTiO3

A. T. Findikoglu, Q. X. Jia, X. D. Wu, G. J. Chen, T. Venkatesan, and D. W. Reagor

Appl. Phys. Lett. 68, 1651 (1996); http://dx.doi.org/10.1063/1.115894 (3 pages) | Cited 48 times

Full Text: | Download PDF

Show Abstract
We have prepared an electrically tunable and adaptive 3‐pole half‐wave bandpass coplanar waveguide filter incorporating a 1.2‐μm‐thick paraelectric SrTiO3 bottom layer and a 0.4‐μm‐thick superconducting YBa2Cu3O7−x top electrode layer on a LaAlO3 substrate. By applying a separate bias voltage on each pole and also on each coupling capacitance of the device at 4 and 76 K, the filter response is not only fine tuned to achieve symmetric and optimized filter characteristics with less than 2% bandwidth centered around 2.5 GHz, but also broadband tuned to shift the passband by more than 15%. © 1996 American Institute of Physics.
Show PACS
85.25.Hv Superconducting logic elements and memory devices; microelectronic circuits

Size distribution of end‐of‐range dislocation loops in silicon‐implanted silicon

G. Z. Pan, K. N. Tu, and S. Prussin

Appl. Phys. Lett. 68, 1654 (1996); http://dx.doi.org/10.1063/1.115895 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
The size and distribution of end‐of‐range dislocation loops in silicon implanted with 50 keV 1016 Si/cm2 and annealed at 750 °C for various times have been studied by transmission electron microscropy. The normalized distribution profile of the dislocation loops has been found to be invariant with time, based on density and size measurement. The profile is quite different from the conventional distribution profile of Oswald ripening in grain growth and precipitate coarsening. Measurement of the total number of interstitials bound in the extrinsic loops shows that the ripening is a conservative process. An explanation for the particular distribution profile is attributed to the stress field associated with the dislocation loops. © 1996 American Institute of Physics.
Show PACS
61.72.Lk Linear defects: dislocations, disclinations
61.80.Jh Ion radiation effects

Effective‐mass Hamiltonian for strained wurtzite GaN and analytical solutions

S. L. Chuang and C. S. Chang

Appl. Phys. Lett. 68, 1657 (1996); http://dx.doi.org/10.1063/1.115896 (3 pages) | Cited 48 times

Full Text: | Download PDF

Show Abstract
We present the effective‐mass Hamiltonian for wurtzite crystals including the strain effects and show analytical solutions for the energy band structures. We found that the Hamiltonian can be block‐diagonalized in our chosen set of basis functions such that the band structures near the zone center can be conveniently derived with analytical solutions. The constant energy surfaces and the valence‐band structures are illustrated graphically. The strain effects on the band structures of the wurtzite GaN are also discussed. This Hamiltonian provides a theoretical foundation for calculating the band structures of the bulk and quantum‐well wurtzite crystals under the framework of the effective mass theory. © 1996 American Institute of Physics.
Show PACS
71.20.Nr Semiconductor compounds
71.55.Eq III-V semiconductors

Effect of ion sputtering on Ge epitaxy on GaAs(110)

X.‐S. Wang, J. Brake, R. J. Pechman, and J. H. Weaver

Appl. Phys. Lett. 68, 1660 (1996); http://dx.doi.org/10.1063/1.115897 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The possibility that ion sputtering could be used to modify the growth mode of Ge on GaAs(110) was investigated by scanning tunneling microscopy. Analysis shows that the nucleation density was significantly increased following vacancy island creation by ion sputtering. The Ge/GaAs(110) structures were thermodynamically stable because of energy gained by saturating dangling bonds at steps. Accordingly, a uniform film could be obtained at a smaller thickness compared to conventional growth. © 1996 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.35.Md Surface thermodynamics, surface energies
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

SiOx luminescence from light‐emitting porous silicon: Support for the quantum confinement/luminescence center model

D. W. Cooke, B. L. Bennett, E. H. Farnum, W. L. Hults, K. E. Sickafus, J. F. Smith, J. L. Smith, T. N. Taylor, P. Tiwari, and A. M. Portis

Appl. Phys. Lett. 68, 1663 (1996); http://dx.doi.org/10.1063/1.115898 (3 pages) | Cited 47 times

Full Text: | Download PDF

Show Abstract
Measurements of hydrogen loss and luminescence as a function of annealing temperature in porous silicon suggest that luminescence is attributable to electron‐hole recombination in SiOx surface layers with an intensity that is dependent upon the surface hydrogen content. The luminescence is composed of three Gaussian bands similar to those found in amorphous SiO2. X‐ray photoelectron spectroscopy and scanning electron microscopy show porous silicon has SiOx on the surface, which is comprised of many particles of about 10 nm size. Collectively, the data strongly support the previously proposed quantum confinement/luminescence center model. © 1996 American Institute of Physics.
Show PACS
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
78.55.Mb Porous materials

Enhancement of electron emission efficiency of Mo tips by diamondlike carbon coatings

F. Y. Chuang, C. Y. Sun, H. F. Cheng, C. M. Huang, and I. N. Lin

Appl. Phys. Lett. 68, 1666 (1996); http://dx.doi.org/10.1063/1.115899 (3 pages) | Cited 48 times

Full Text: | Download PDF

Show Abstract
The effect of diamondlike carbon (DLC) films coated by pulsed laser deposition technique on the electron emission characteristics of Mo tips is examined. Turn‐on voltage (V0) was lowered from 40 V for Mo tips to 22 V for DLC coated Mo tips and maximum anode current (IA) was increased from ∼44 μA for Mo tips to ∼2.0 mA for DLC coated Mo tips. Maximum anode current (IA) for the DLC coated Mo tips, however, decreased during operation. Raman spectroscopy and selected area diffraction (SAD) in transmission electron microscopy (TEM) revealed that the degradation of electron emission behavior can be ascribed to the conversion of sp3‐bonds, characteristic for diamond, to sp2‐bonds, characteristics for graphite. The transformation of the structure is assumed to be induced by the local heat from the DLC coatings. © 1996 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
81.15.Fg Pulsed laser ablation deposition
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close