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

25 Jan 1999

Volume 74, Issue 4, pp. 483-629

Return to All Sections
back to top
RSS Feeds

Time-resolved photoluminescence studies of an ionized donor-bound exciton in GaN

R. A. Mair, J. Li, S. K. Duan, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 74, 513 (1999); http://dx.doi.org/10.1063/1.123171 (3 pages) | Cited 17 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Time-resolved photoluminescence (PL) spectroscopy has been used to study the radiative recombination of excitons bound to ionized donors in GaN doped with both Mg and Si at concentrations of 5×1018/cm3 and 1.5×1017/cm3, respectively. Low temperature (T ∼ 10K) time-resolved, as well as integrated PL spectra, identify an ionized donor-bound (Si) exciton peak (D+X) approximately 11.5 meV below and a neutral acceptor-bound exciton (A0X) 20.5 meV below the free exciton peak. Rapid decay of the free exciton emission (⩽20 ps) implies that excitons are quickly captured by acceptors and ionized donors. We find the (A0X) emission lifetime is consistent with previous measurements for GaN:Mg epilayers, while the (D+X) lifetime of 160 ps is longer than that of the well studied neutral donor-bound exciton (D0X). The measured (D+X) lifetime, in comparison with (D0X) and (A0X), suggests that the state is stable at low temperature. © 1999 American Institute of Physics.
Show PACS
78.55.Cr III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics
71.35.Gg Exciton-mediated interactions
71.55.Eq III-V semiconductors

Hydrogen-induced reduction of axial stress in optical fiber cores

Nguyen Hong Ky, H. G. Limberger, R. P. Salathé, F. Cochet, and L. Dong

Appl. Phys. Lett. 74, 516 (1999); http://dx.doi.org/10.1063/1.123172 (3 pages) | Cited 8 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Radial distributions of axial stress across B/Ge- and Sn/Ge-codoped core fibers and a Corning standard single-mode fiber were measured before and after hydrogen loading under different conditions. A significant reduction of axial stress in the core of all investigated fibers is observed after hydrogen loading. The stress reduction in the core of hydrogen-loaded fibers is irreversible and depends strongly on the core dopants and the fiber drawing tension. The hydrogen-induced core stress reduction is believed to be related to the reactions between hydrogen and drawing-induced defects in the fiber core. © 1999 American Institute of Physics.
Show PACS
42.81.Bm Fabrication, cladding, and splicing

Optically induced surface relief phenomena in azobenzene polymers

N. C. R. Holme, L. Nikolova, S. Hvilsted, P. H. Rasmussen, R. H. Berg, and P. S. Ramanujam

Appl. Phys. Lett. 74, 519 (1999); http://dx.doi.org/10.1063/1.123173 (3 pages) | Cited 30 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Azobenzene polymers and oligomers show intriguing surface relief features when irradiated with polarized laser light. We show through atomic force microscopic investigation of side-chain azobenzene polymers after irradiation through an amplitude mask that large peaks or trenches result depending on the architecture of the polymer. Extensive mass transport over long distances has been observed, paving the way for easy replication of nanostructures. We also show that it is possible to store microscopic images as topographic features in the polymers just through polarized light irradiation. © 1999 American Institute of Physics.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
79.20.Ds Laser-beam impact phenomena

Mechanism for interfacial adhesion strength of an ion beam mixed Cu/polyimide with a thin buffer layer

G. S. Chang, K. H. Chae, C. N. Whang, E. Z. Kurmaev, D. A. Zatsepin, R. P. Winarski, D. L. Ederer, A. Moewes, and Y. P. Lee

Appl. Phys. Lett. 74, 522 (1999); http://dx.doi.org/10.1063/1.123174 (3 pages) | Cited 12 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A Cu (400 Å)/Al (50 Å)/polyimide system showed larger adhesion strength than that of Cu (400 Å)/polyimide after N2+ ion beam mixing. X-ray emission spectroscopy was performed to elucidate the mechanism of adhesion enhancement of the ion beam mixed Cu (400 Å)/polyimide with a thin Al buffer layer. Cu L2,3 x-ray emission spectra showed the formation of a CuAl2O4 layer which is strongly correlated with the large adhesion strength of a Cu/Al/polyimide. A decrease in adhesion strength at an ion dose higher than 5×1015 cm−2 was also explained by the formation of an amorphous carbon. This was understood by investigating C Kα x-ray emission spectra. The overall spectroscopic results were in accordance with the behavior of quantitative adhesion strength. © 1999 American Institute of Physics.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.35.Gy Mechanical properties; surface strains
78.70.En X-ray emission spectra and fluorescence
78.66.Qn Polymers; organic compounds
61.41.+e Polymers, elastomers, and plastics
68.55.Nq Composition and phase identification

Fabrication of nano-structural arrays by channeling pulsed atomic beams through pulsed-laser standing-waves under off-resonant condition

X. D. Zhu

Appl. Phys. Lett. 74, 525 (1999); http://dx.doi.org/10.1063/1.123175 (3 pages) | Cited 3 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show that it is feasible to produce one- and two-dimensional nano-structure arrays by passing microsecond pulsed atomic beams through microsecond laser standing-wave patterns under completely off-resonant condition. This method enables fabrication of vertically heterogeneous nanostructures such as multilayers with one pulsed laser system. © 1999 American Institute of Physics.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
61.46.-w Structure of nanoscale materials
42.62.-b Laser applications

The effect of native oxide on epitaxial SiGe from deposited amorphous Ge on Si

Y. H. Wu, W. J. Chen, Albert Chin, and C. Tsai

Appl. Phys. Lett. 74, 528 (1999); http://dx.doi.org/10.1063/1.123176 (3 pages) | Cited 17 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the effect of native oxide on the epitaxial SiGe from deposited amorphous Ge on Si. Instead of epitaxial growth by molecular beam epitaxy or ultrahigh-vacuum chemical vapor deposition, the SiGe layer is formed by this simple process followed by an annealing step. As observed by transmission electron microscopy, the suppression of native oxide plays an important role to achieve epitaxial SiGe. The SiGe quality degrades with increasing native oxide thickness and becomes polycrystalline with a ∼ 20 Å interfacial native oxide. On the other hand, single crystalline SiGe can be routinely formed from a HF-vapor treated Si surface. © 1999 American Institute of Physics.  
Show PACS
68.55.-a Thin film structure and morphology
81.05.Hd Other semiconductors
81.15.Np Solid phase epitaxy; growth from solid phases
68.35.Fx Diffusion; interface formation
66.30.Ny Chemical interdiffusion; diffusion barriers
61.72.Cc Kinetics of defect formation and annealing
81.65.Cf Surface cleaning, etching, patterning
81.65.Mq Oxidation

Metastable surface ordering in strain relaxed Si0.5Ge0.5 epitaxial layers grown at high temperature

H. Reichert, S. C. Moss, P. Imperatori, and K. Evans-Lutterodt

Appl. Phys. Lett. 74, 531 (1999); http://dx.doi.org/10.1063/1.123177 (3 pages) | Cited 3 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied compositional ordering in the near surface region of 3500 Å thick unstrained Si0.5Ge0.5(001) samples grown by chemical vapor deposition. Measuring asymptotic Bragg scattering along integer and half-integer truncation rods, we found a type of metastable ordering at this surface which is characterized by integer/half-integer reflections along the integer order truncation rods. We show unambiguously that those scattering features originate from a thin layer at the surface. Annealing at 750 °C extinguished these reflections irreversibly, while the reflections of the RS3 bulk structure were not affected. Anomalous scattering at the Ge K edge also confirmed the existence of a new structure in the near surface region. © 1999 American Institute of Physics.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Rh Phase transitions and critical phenomena
68.35.Dv Composition, segregation; defects and impurities
68.55.-a Thin film structure and morphology
61.72.Cc Kinetics of defect formation and annealing

Asymmetric electro-optical response in a liquid crystal cell containing a layer of amorphous tungsten trioxide

G. Strangi, D. E. Lucchetta, E. Cazzanelli, N. Scaramuzza, C. Versacé, and R. Bartolino

Appl. Phys. Lett. 74, 534 (1999); http://dx.doi.org/10.1063/1.123178 (3 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this work, we present the experimental evidence of a polarity sensitive electro-optic response in a nematic liquid crystal. The liquid crystal cell was made by using a standard sandwich configuration, with one of the indium tin oxide electrodes covered by a thin layer of tungsten trioxide (WO3), deposited by sputtering. The optical response was inhibited when the electrode covered by WO3 film was anodically charged, while the usual optical response occurred under a reverse field. An ionic diffusion process was associated with the establishment of an internal electric field, which inhibited unipolarly the optical switching. © 1999 American Institute of Physics.
Show PACS
78.20.Jq Electro-optical effects
78.66.Nk Insulators
81.15.Cd Deposition by sputtering

1.5 μm infrared photoluminescence phenomena in Er-doped porous silicon

M. Stepikhova, L. Palmetshofer, W. Jantsch, H. J. von Bardeleben, and N. V. Gaponenko

Appl. Phys. Lett. 74, 537 (1999); http://dx.doi.org/10.1063/1.123179 (3 pages) | Cited 14 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We analyze the photoluminescence (PL) in nanoporous Si (po-Si) doped with Er by electrochemical deposition and by spin-on doping. Two kinds of optically active Er centers appear in electrochemically doped po-Si with the main sharp and intense lines at 1.548 and 1.539 μm, respectively. The features characteristic for the spin-on doping method are: intense dislocation-related PL at 1.53 μm and strong luminescent activity of the silica gel used for Er doping. High-temperature PL observed up to 360 K is attributed to Er centers incorporated in the silica-like matrix at the oxidized surface of electrochemically doped po-Si and in erbium-containing silica gel. © 1999 American Institute of Physics.
Show PACS
78.55.Ap Elemental semiconductors
78.55.Mb Porous materials
78.66.Db Elemental semiconductors and insulators
71.55.Cn Elemental semiconductors

Electrical and optical properties of Ge–implanted 4H–SiC

G. Katulka, C. Guedj, J. Kolodzey, R. G. Wilson, C. Swann, M. W. Tsao, and J. Rabolt

Appl. Phys. Lett. 74, 540 (1999); http://dx.doi.org/10.1063/1.123186 (3 pages) | Cited 13 times

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
The structural, electronic, and optical properties of single crystalline n-type 4H–SiC implanted with Ge atoms have been investigated through x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Raman spectroscopy, and sheet resistivity measurements. Ge atoms are implanted under the conditions of a 300 keV ion beam energy with a dose of 2×1016 cm−2. X-ray diffraction of the Ge-implanted sample showed broadening of the Bragg peaks. A shoulder on the (0004) reflection indicated an increase in the lattice constant corresponding to substitutional Ge and implantation induced lattice damage, which was repaired through thermal annealing at 1000 °C. The diffraction pattern after annealing indicated improved crystal structure and a peak shift to a lower reflection angle of 35.2°. The composition of Ge detected through XRD was reasonably consistent with RBS measurements that indicated 1.2% Ge in a 1600-Å-thick layer near the SiC surface. Raman spectroscopy also showed fundamental differences in the spectra obtained for the Ge-implanted SiC (SiC:Ge) compared to a pure sample of SiC. Sheet resistivity measurements indicate a higher conductivity in the Ge implant by a factor of 1.94 compared to unimplanted SiC. These results have demonstrated the possibility of substitutional implantation of Ge atoms into the crystalline lattice of 4H–SiC substrates. The change in composition and properties may have numerous electronic device applications including high power, high temperature, optoelectronic, as well as high frequency device structures. © 1999 American Institute of Physics.
Show PACS
72.80.Jc Other crystalline inorganic semiconductors
61.72.up Other materials
61.82.Fk Semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.80.Jh Ion radiation effects
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close