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 Dec 1999

Volume 75, Issue 25, pp. 3905-4030

Return to All Sections
back to top
RSS Feeds

Efficient route to large arrays of CNx nanofibers by pyrolysis of ferrocene/melamine mixtures

M. Terrones, H. Terrones, N. Grobert, W. K. Hsu, Y. Q. Zhu, J. P. Hare, H. W. Kroto, D. R. M. Walton, Ph. Kohler-Redlich, M. Rühle, J. P. Zhang, and A. K. Cheetham

Appl. Phys. Lett. 75, 3932 (1999); http://dx.doi.org/10.1063/1.125498 (3 pages) | Cited 89 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report a high-yield route to two-dimensional arrays (<400×400 μm2) of aligned C49Nx (x ⩽ 1) nanofibers (<100 nm o.d.; <60 μm length), by pyrolyzing mixtures of ferrocene and melamine at 950–1050 °C under an Ar flow. The fibers exhibit unusual interlinked stacked-cone morphologies, ascribed to the presence of nitrogen. High-resolution electron energy-loss spectroscopy of the individual fibers reveals a 2% nitrogen content with ionization energies mainly at ∼400.9 eV, corresponding to N bonded to three C atoms within a hexagonal framework. The nanofibers may be useful for the economic fabrication of field emission sources and robust composites. © 1999 American Institute of Physics.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
61.46.-w Structure of nanoscale materials
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
79.20.Kz Other electron-impact emission phenomena

Defect examination of diamond crystals by surface hydrogen-plasma etching

X. Jiang and C. Rickers

Appl. Phys. Lett. 75, 3935 (1999); http://dx.doi.org/10.1063/1.125499 (3 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method to examine the defects and defect distribution in diamond crystals has been developed. To make the crystal defects visible, a high-temperature hydrogen-plasma etching was employed. By a combination of scanning electron microscopy and atomic force microscopy, the etch pits of the (001) diamond faces parallel to the substrate were observed and analyzed. The defect distribution of chemical-vapor-deposited diamond crystallites corresponds exactly with that observed by transmission electron microscopy, and can be related to the growth mode during film deposition. © 1999 American Institute of Physics.
Show PACS
81.05.ub Fullerenes and related materials
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.65.Cf Surface cleaning, etching, patterning
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Hydrogen blister depth in boron and hydrogen coimplanted n-type silicon

T. Höchbauer, M. Nastasi, and J. W. Mayer

Appl. Phys. Lett. 75, 3938 (1999); http://dx.doi.org/10.1063/1.125500 (3 pages) | Cited 11 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the depths of hydrogen surface blisters in 〈100〉 n-type silicon, which formed after B+H coimplantation and heat treatment. The silicon substrates had three different dopant levels, ranging from 1014 to 1019 cm−3. The Si substrates were first implanted with B+ ions at 147 keV to a dose of 1015 cm−2. Some of the B-implanted samples were left in their as-implanted state; others were electrically activated by a rapid thermal anneal. The samples were then implanted with 40 keV H+ to a dose of 5×1016 cm−2. At the chosen implantation energies, the hydrogen- and boron-implantation distributions overlap. Following H+ implantation, all the samples were vacuum annealed and examined by ion-beam analysis and scanning electron microscopy. In all cases, the blister depth was consistently found to be strongly correlated with the H damage profile rather than the H or B concentration profiles. © 1999 American Institute of Physics.
Show PACS
61.72.uf Ge and Si
61.72.Cc Kinetics of defect formation and annealing
85.40.Ry Impurity doping, diffusion and ion implantation technology
61.72.S- Impurities in crystals

Correlating the location of structural defects with the electrical failure of multiwalled carbon nanotubes

P. J. de Pablo, S. Howell, S. Crittenden, B. Walsh, E. Graugnard, and R. Reifenberger

Appl. Phys. Lett. 75, 3941 (1999); http://dx.doi.org/10.1063/1.125501 (3 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electrical failure of carbon nanotubes was investigated by obtaining I(V) data with a voltage ramp from a rope of multiwalled carbon nanotubes. Noncontact scanning force microscope images were obtained before and after each I(V) curve until electrical failure of the tube resulted. Following this procedure, it was possible to correlate a defect on the surface of a nanotube with the exact location of the tube failure. © 1999 American Institute of Physics.
Show PACS
61.48.-c Structure of fullerenes and related hollow and planar molecular structures
72.80.Rj Fullerenes and related materials
81.05.ub Fullerenes and related materials
61.72.-y Defects and impurities in crystals; microstructure
77.22.Jp Dielectric breakdown and space-charge effects
68.35.B- Structure of clean surfaces (and surface reconstruction)

Radiative recombination centers induced by stacking-fault pairs in ZnSe/ZnMgSSe quantum-well structures

D. Lüerßen, R. Bleher, H. Richter, Th. Schimmel, H. Kalt, A. Rosenauer, D. Litvinov, A. Kamilli, D. Gerthsen, K. Ohkawa, B. Jobst, and D. Hommel

Appl. Phys. Lett. 75, 3944 (1999); http://dx.doi.org/10.1063/1.125502 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stacking-fault pairs in ZnSe/ZnMgSSe quantum-well structures are found to induce enhanced radiative recombination visible as pairs of bright spots in microphotoluminescence intensity maps. Structural investigation by atomic-force microscopy and transmission electron microscopy (plan view as well as cross section) reveal that a widening and bending of quantum wells occurs when they are intersected by Frank-type stacking faults. The enlargement of the well width by up to 12 bilayers evokes an efficient localization of excitons. The localizing potential related to Shockley-type stacking-fault pairs is found to be much shallower. © 1999 American Institute of Physics.
Show PACS
78.66.Hf II-VI semiconductors
73.61.Ga II-VI semiconductors
78.55.Et II-VI semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
61.72.Nn Stacking faults and other planar or extended defects
68.35.Ct Interface structure and roughness
71.35.Cc Intrinsic properties of excitons; optical absorption spectra
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Oxygen pressure-tuned epitaxy and optoelectronic properties of laser-deposited ZnO films on sapphire

S. Choopun, R. D. Vispute, W. Noch, A. Balsamo, R. P. Sharma, T. Venkatesan, A. Iliadis, and D. C. Look

Appl. Phys. Lett. 75, 3947 (1999); http://dx.doi.org/10.1063/1.125503 (3 pages) | Cited 150 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Influence of oxygen pressure on the epitaxy, surface morphology, and optoelectronic properties has been studied in the case of ZnO thin films grown on sapphire (0001) by pulsed-laser deposition. Results of Rutherford backscattering and ion channeling in conjunction with atomic force microscopy clearly indicate that the growth mode, degree of epitaxy, and the defect density strongly depend on the oxygen background pressure during growth. It is also found that the growth mode and the defects strongly influence the electron mobility, free-electron concentration, and the luminescence properties of the ZnO films. By tuning the oxygen pressure during the initial and the final growth stages, smooth and epitaxial ZnO films with high optical quality, high electron mobility, and low background carrier concentration have been obtained. The implication of these results towards the fabrication of superlattices and controlled n- and p-type doping is discussed. © 1999 American Institute of Physics.
Show PACS
81.15.Fg Pulsed laser ablation deposition
81.05.Dz II-VI semiconductors
73.61.Ga II-VI semiconductors
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.50.Dn Low-field transport and mobility; piezoresistance
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Phase separation in InGaN multiple quantum wells annealed at high nitrogen pressures

L. T. Romano, M. D. McCluskey, C. G. Van de Walle, J. E. Northrup, D. P. Bour, M. Kneissl, T. Suski, and J. Jun

Appl. Phys. Lett. 75, 3950 (1999); http://dx.doi.org/10.1063/1.125504 (3 pages) | Cited 18 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Phase separation was found to occur in In0.33Ga0.67N/GaN multiple-quantum-well structures after annealing at 975 °C in a hydrostatic pressure of 5 kbar N2 for 4 h. X-ray diffraction (XRD) spectra of the as-grown samples showed superlattice peaks that were replaced by a broad, single-phase peak after annealing. Transmission electron microscopy (TEM) images of the annealed samples show In-rich precipitates and voids that are found only within the quantum-well region. Both TEM and XRD measurements indicated that the formation of voids and second phases were suppressed after annealing in a hydrostatic pressure of 15 kbar. In addition, optical absorption measurements on these samples showed no indication of a peak at 2.65 eV that was observed in previous annealing studies. © 1999 American Institute of Physics.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
64.75.-g Phase equilibria
61.72.Cc Kinetics of defect formation and annealing
62.50.-p High-pressure effects in solids and liquids
78.66.Fd III-V semiconductors
78.40.Fy Semiconductors
61.72.Qq Microscopic defects (voids, inclusions, etc.)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close