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

28 Oct 2002

Volume 81, Issue 18, pp. 3311-3500

Return to All Sections
back to top
RSS Feeds

Ab initio calculations of vacancies in SixGe1−x

G. M. Dalpian, P. Venezuela, Antônio J. R. da Silva, and A. Fazzio

Appl. Phys. Lett. 81, 3383 (2002); http://dx.doi.org/10.1063/1.1517172 (3 pages) | Cited 7 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ab initio calculations are used to investigate the structural and electronic properties of vacancies in SixGe1−x. The (++), (+), (0), and (−) charge states are studied and the substitutional disorder of the alloy is considered explicitly. We found a linear relationship between the effective-U for the system formed by the (++), (+), and (0) charge states and the number of Si atoms in the first neighborhood of a vacancy (NSi). The effective-U is positive when NSi is zero, and it is negative when NSi is 2 and 4. In all cases, the absolute value of the effective-U in the alloy is significantly smaller than its value for pure Si and pure Ge. © 2002 American Institute of Physics.
Show PACS
71.55.Ht Other nonmetals
61.72.J- Point defects and defect clusters
71.15.-m Methods of electronic structure calculations

Upside-down tuning of light- and heavy-hole states in GaNAs/GaAs single quantum wells by thermal expansion and quantum confinement

M. H. Ya, W. Z. Cheng, Y. F. Chen, and T. Y. Lin

Appl. Phys. Lett. 81, 3386 (2002); http://dx.doi.org/10.1063/1.1518777 (3 pages) | Cited 4 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polarization resolved photoluminescence from a cleaved sample edge (edge photoluminescence) was used to investigate the valence-band splitting in GaNAs/GaAs single quantum wells. The spectra resulting from the heavy- and light-hole transitions shows an interesting phenomenon, in which the light-hole state is above the heavy-hole state at low temperatures, they degenerate at about 195 K, and finally the light-hole state is below the heavy-hole state at higher temperatures. We point out that the underlying origin of our observation can be attributed to the competitive effect between the tensile strain induced by lattice mismatch and quantum confinement. It is known that the large density of heavy-hole states is beneficial for laser diodes. Our result is therefore very useful for the application of GaNAs/GaAs quantum wells in optical devices. © 2002 American Institute of Physics.
Show PACS
73.21.Fg Quantum wells
78.67.De Quantum wells
81.07.St Quantum wells
78.55.Cr III-V semiconductors
81.05.Ea III-V semiconductors
68.65.Fg Quantum wells
65.40.De Thermal expansion; thermomechanical effects

Angle-dependent x-ray absorption spectroscopy study of Zn-doped GaN

J. W. Chiou, S. Mookerjee, K. V. R. Rao, J. C. Jan, H. M. Tsai, K. Asokan, W. F. Pong, F. Z. Chien, M.-H. Tsai, Y. K. Chang, Y. Y. Chen, J. F. Lee, C. C. Lee, and G. C. Chi

Appl. Phys. Lett. 81, 3389 (2002); http://dx.doi.org/10.1063/1.1518776 (3 pages) | Cited 9 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
As-grown and Zn-implanted wurtzite GaN samples have been studied by angle-dependent x-ray absorption near edge structure (XANES) measurements at the N and Ga K-edges and the Ga L3-edge. The angle dependence of the XANES spectra shows that the Ga–N bonds lying in the bilayer have lower energies than bonds along the c-axis, which can be attributed to the polar nature of the GaN film. The comparison of the Ga L3-edge XANES spectra of as-grown and Zn-doped GaN reveals significant dopant induced enhancement of near-edge Ga d-derived states. © 2002 American Institute of Physics.
Show PACS
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
61.72.uj III-V and II-VI semiconductors

Frequency characterization and modeling of interface traps in HfSixOy/HfO2 gate dielectric stack from a capacitance point-of-view

Pascal Masson, Jean-Luc Autran, Michel Houssa, Xavier Garros, and Charles Leroux

Appl. Phys. Lett. 81, 3392 (2002); http://dx.doi.org/10.1063/1.1518561 (3 pages) | Cited 31 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A time-resolved analysis of the capacitance–voltage (C–V) technique and an inverse modeling approach have been developed to determine the energy distribution and the capture cross section of interface traps in the silicon band gap from multifrequency C–V measurements. In this work, our method is performed on n-type metal-oxide-semiconductor capacitors with HfSixOy/HfO2 gate dielectric stack and polysilicon gate. From the frequency dispersion of C–V data, we evidence a peak of acceptor states in the upper half of the band gap at 0.81 eV above the valence band and characterized by a capture cross section of 1.5×10−17 cm2. This value is approximately ten times lower than typical capture cross sections relative to the dangling bonds (Pb centers) at the Si/SiO2 interface, which is in good agreement with a Coulombic center model predicting a capture cross section inversely proportional to the square of the dielectric permittivity. © 2002 American Institute of Physics.
Show PACS
73.20.Hb Impurity and defect levels; energy states of adsorbed species
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
81.05.Cy Elemental semiconductors
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
71.20.Mq Elemental semiconductors
71.55.Cn Elemental semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
77.22.Ch Permittivity (dielectric function)
77.55.-g Dielectric thin films

Lifetime of nonequilibrium zone-center longitudinal optical phonons in zinc-blende materials

Saswati Barman and G. P. Srivastava

Appl. Phys. Lett. 81, 3395 (2002); http://dx.doi.org/10.1063/1.1517170 (3 pages) | Cited 10 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We employ a theoretical model to assess the importance of Ridley’s channel in limiting the lifeitime of nonequilibrium zone-center LO phonons in zinc-blende materials. For comparison, we also present results for the decay through Klemens’s channel as well as via Vallée–Bogani’s intraband combination channel. © 2002 American Institute of Physics.
Show PACS
63.20.-e Phonons in crystal lattices

Effects of hydrostatic and uniaxial stress on the conductivity of p-type GaN epitaxial layer

Y. Liu, M. Z. Kauser, M. I. Nathan, P. P. Ruden, A. M. Dabiran, B. Hertog, and P. P. Chow

Appl. Phys. Lett. 81, 3398 (2002); http://dx.doi.org/10.1063/1.1517713 (3 pages) | Cited 8 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present experimental results on the dependence of the electrical conductivity of Mg-doped, p-type GaN on hydrostatic pressure and uniaxial stress. The samples were grown by molecular beam epitaxy on sapphire substrates. Hydrostatic pressure over the range studied (0–7 kbar) leads to a relatively small decrease in the conductivity. Uniaxial stress in the basal plane results in strongly increasing conductivity parallel to the stress direction and in weakly decreasing conductivity perpendicular to the stress direction. We relate the observed symmetry of the piezoconductivity to deformation potential induced changes in the band structure near the top of the valence band. © 2002 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
62.50.-p High-pressure effects in solids and liquids
71.20.Nr Semiconductor compounds

Electron transport studies on In0.30Ga0.70As/GaAs-quantum-well infrared photodetectors using time-resolved photocurrent measurements

S. Steinkogler, H. Schneider, R. Rehm, M. Walther, and P. Koidl

Appl. Phys. Lett. 81, 3401 (2002); http://dx.doi.org/10.1063/1.1518153 (3 pages) | Cited 3 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the time-resolved photocurrent response of an InGaAs/GaAs quantum-well infrared photodetector stimulated by infrared fs-laser pulses ( ∼ 9 μm wavelength). We observe two dynamic photocurrent components, which are driven by the optical excitation and by the photoinduced space charge, respectively. The ratio of the time-averaged values of these two components allows us to determine the photoconductive gain. These gain values exhibit a good quantitative agreement with the gain obtained from continuous waves measurements of the peak responsivity. Furthermore, we present a detailed study of the decay time constant of the slow component as a function of the temperature and the bias voltage and compare our results with a recent theoretical model. © 2002 American Institute of Physics.
Show PACS
73.63.Hs Quantum wells
78.67.De Quantum wells
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
78.30.Fs III-V and II-VI semiconductors
73.50.Pz Photoconduction and photovoltaic effects
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Explanation for the leakage current in polycrystalline-silicon thin-film transistors made by Ni-silicide mediated crystallization

P. J. van der Zaag, M. A. Verheijen, S. Y. Yoon, and N. D. Young

Appl. Phys. Lett. 81, 3404 (2002); http://dx.doi.org/10.1063/1.1517406 (3 pages) | Cited 29 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The source of the leakage current in polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) made by Ni-mediated crystallization has been investigated. Studies of TFTs and of the crystallization process by in situ transmission electron microscopy show that the crystallization process is a two-stage process and that the cause of the leakage problem is associated with incomplete crystallization of amorphous-Si. By removing the last pockets of amorphous-Si, for instance, by long anneals, poly-Si TFTs can be made with adequately low leakage current <1 pA/μm (at a source–drain voltage of 5 V) for display applications, despite the presence of Ni up to 2.5×1019 atoms/cm3. © 2002 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
85.30.De Semiconductor-device characterization, design, and modeling
68.37.Lp Transmission electron microscopy (TEM)
81.40.Gh Other heat and thermomechanical treatments

As-mediated stacking fault in wurtzite GaN epilayers

Hyonju Kim, T. G. Andersson, J.-M. Chauveau, and A. Trampert

Appl. Phys. Lett. 81, 3407 (2002); http://dx.doi.org/10.1063/1.1519096 (3 pages) | Cited 4 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Growth of a thin GaAs layer embedded in wurtzite GaN was performed on sapphire (0001) by rf-plasma assisted molecular-beam epitaxy. A well-confined As-rich layer with a tail in the cap layer was measured by secondary ion mass spectrometry. Transmission electron microscopy studies demonstrated the formation of basal plane stacking faults, which were correlated with the presence of As in the layer. High-resolution microscopy revealed the stacking fault as a thin platelike cubic inclusion in the hexagonal GaN. © 2002 American Institute of Physics.
Show PACS
68.65.Ac Multilayers
61.72.Nn Stacking faults and other planar or extended defects
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.37.Lp Transmission electron microscopy (TEM)

Ultrathin silicon dioxide layers with a low leakage current density formed by chemical oxidation of Si

Asuha, Takuya Kobayashi, Osamu Maida, Morio Inoue, Masao Takahashi, Yoshihiro Todokoro, and Hikaru Kobayashi

Appl. Phys. Lett. 81, 3410 (2002); http://dx.doi.org/10.1063/1.1517723 (3 pages) | Cited 34 times

Online Publication Date: 22 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Chemical oxidation of Si by use of azeotrope of nitric acid and water can form 1.4-nm-thick silicon dioxide layers with a leakage current density as low as those of thermally grown SiO2 layers. The capacitance–voltage (C–V) curves for these ultrathin chemical SiO2 layers have been measured due to the low leakage current density. The leakage current density is further decreased to ∼ 1/5 (cf. 0.4 A/cm2 at the forward gate bias of 1 V) by post-metallization annealing at 200 °C in hydrogen. Photoelectron spectroscopy and C–V measurements show that this decrease results from (i) increase in the energy discontinuity at the Si/SiO2 interface, and (ii) elimination of Si/SiO2 interface states and SiO2 gap states. © 2002 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.61.Ng Insulators
81.65.Mq Oxidation
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
79.60.Jv Interfaces; heterostructures; nanostructures
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close