jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

15 Oct 2005

Volume 98, Issue 8, Articles (08xxxx)

Return to All Sections
back to top
RSS Feeds

Monte Carlo calculations of static and dynamic electron transport in nitrides

E. Starikov, P. Shiktorov, V. Gruinskis, L. Varani, J. C. Vaissière, C. Palermo, and L. Reggiani

J. Appl. Phys. 98, 083701 (2005); http://dx.doi.org/10.1063/1.2089187 (7 pages) | Cited 5 times

Online Publication Date: 18 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monte Carlo simulation of high-field transport in semiconductor nitrides GaN and InN is used to calculate the velocity field and the high-frequency behavior of differential mobility, spectral density of velocity fluctuations, and noise temperature. The spectra of hot-carrier differential mobility and velocity noise are found to exhibit a plateau in the low-frequency region, a peak at intermediate frequencies, and a 1/f2 decay at the highest frequencies. The comparison with standard A3B5 compounds shows that the characteristic frequencies associated with extreme and cutoff decay of the negative differential mobility, etc., are shifted to a higher-frequency range for the case of nitrides. This property is favorable for applications of nitrides in the terahertz frequency range.
Show PACS
72.70.+m Noise processes and phenomena
72.20.Ht High-field and nonlinear effects
72.30.+q High-frequency effects; plasma effects
72.80.Ey III-V and II-VI semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance

Thermoelectric properties of Te-doped CoSb3 by spark plasma sintering

X. Y. Li, L. D. Chen, J. F. Fan, W. B. Zhang, T. Kawahara, and T. Hirai

J. Appl. Phys. 98, 083702 (2005); http://dx.doi.org/10.1063/1.2067704 (6 pages) | Cited 21 times

Online Publication Date: 19 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Te-doped CoSb3 bulk polycrystalline materials Co4Sb12−xTex have been prepared by melting, annealing, and spark plasma sintering and have been characterized by x-ray diffraction. From the lattice constants of the Te-doped samples, a Te substituting fraction limit for Sb is estimated to be x = 0.55. The Hall effect, Seebeck coefficient, electrical-conductivity, and thermal-conductivity measurements were performed between room temperature and 900 K. The Te-doped materials Co4Sb12−xTex show an n-type conduction. As the Te fraction increases, the electron concentration and the electrical conductivity of the samples increase, while the Hall mobility, the absolute Seebeck coefficient, and the thermal conductivity decrease. A maximum dimensionless figure of merit of 0.72 is obtained at 850 K for Co4Sb11.5Te0.5.
Show PACS
72.15.Jf Thermoelectric and thermomagnetic effects
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys
52.77.-j Plasma applications
64.70.D- Solid-liquid transitions
81.40.Gh Other heat and thermomechanical treatments
61.66.Dk Alloys
72.15.Gd Galvanomagnetic and other magnetotransport effects
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
61.72.S- Impurities in crystals

Electronic properties and tunability in Si quantum rings

Amjad Y. Nazzal, Huaxiang Fu, and Lin-Wang Wang

J. Appl. Phys. 98, 083703 (2005); http://dx.doi.org/10.1063/1.2089165 (4 pages) | Cited 2 times

Online Publication Date: 20 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present an unconventional scheme that is able to dramatically modify single-electron states as well as their couplings in semiconductor nanostructures. The approach consists in perturbing the wave-function core (rather than the insignificant tail) of nanostructure states. We demonstrate this approach using a structure of silicon quantum rings. Anomalous interstate mixing, large tunability of orbital energy, and uncommon s/p level crossing are predicted.
Show PACS
71.20.Mq Elemental semiconductors
73.22.Dj Single particle states
73.20.At Surface states, band structure, electron density of states

Electron transport through hierarchical self-assembly of GaAs/AlxGa1−xAs quantum dots

Shu-Shen Li, Jian-Bai Xia, and Kenji Hirose

J. Appl. Phys. 98, 083704 (2005); http://dx.doi.org/10.1063/1.2108152 (3 pages) | Cited 6 times

Online Publication Date: 20 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The transmission of electrons through a hierarchical self-assembly of GaAs/AlxGa1−xAs quantum dots (QDs) is calculated using the coupled-channel recursion method. Our results reveal that the number of conductance peaks does not change when the barrier widths change, but the intensities decrease as the barrier widths increase. The conductance peaks will shift towards low Fermi energies as the transverse width of GaAs QD increases, as the thickness of GaAs quantum well increases, or as the height of GaAs QDs decreases. Our calculated results may be useful in the application of QDs to photoelectric devices.
Show PACS
73.63.Kv Quantum dots
73.61.Ey III-V semiconductors
68.65.Hb Quantum dots (patterned in quantum wells)
73.21.La Quantum dots
73.21.Fg Quantum wells

Characterization of the physical and electrical properties of Indium tin oxide on polyethylene napthalate

H. Han, Daniel Adams, J. W. Mayer, and T. L. Alford

J. Appl. Phys. 98, 083705 (2005); http://dx.doi.org/10.1063/1.2106013 (8 pages) | Cited 30 times

Online Publication Date: 21 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Indium tin oxide (ITO) thin films, on polyethylene napthalate (PEN) of both good electrical and optical properties were obtained by radio-frequency sputtering. The optoelectronic properties of the ITO films on PEN substrate were evaluated in terms of the oxygen content and the surface morphology. Rutherford backscattering spectrometry analysis was used to determine the oxygen content in the film. Hall-effect measurements were used to evaluate the dependence of electrical properties on oxygen content. The results showed that the resistivity of the ITO film increases with increasing oxygen content. For an oxygen content of 1.6×1018–2.48×1018 atoms/cm2, the resistivity varied from 0.38×10−2 to 1.86×10−2 Ω cm. Typical resistivities were about ∼ 10−3 Ω cm. UV-Vis spectroscopy and atomic force microscopy measurements were used to determine the optical transmittance and surface roughness of ITO films, respectively. Optical transmittances of ∼ 85% were obtained for the ITO thin films. Our results revealed that substrate roughness were translated onto the deposited ITO thin layers. The ITO surface roughness influences both the optical and electrical properties of the thin films. For a 125 μm PEN substrate the roughness is 8.4 nm, whereas it is 3.2 nm for 200 μm substrate thicknesses. The optical band gap is about 3.15 eV for all ITO film and is influenced by the polymer substrate. A model is proposed that the optical transmittance in the visible region is governed by the carrier concentration in the ITO thin films.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
78.66.Li Other semiconductors
73.61.Le Other inorganic semiconductors
68.55.-a Thin film structure and morphology
68.55.A- Nucleation and growth
68.37.Ps Atomic force microscopy (AFM)
68.60.Wm Other nonelectronic physical properties
71.20.Nr Semiconductor compounds
78.40.Fy Semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
81.15.Cd Deposition by sputtering
82.80.-d Chemical analysis and related physical methods of analysis
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Space-charge waves in silicon carbide

M. P. Petrov, V. V. Bryksin, A. A. Lebedev, M. Lemmer, and M. Imlau

J. Appl. Phys. 98, 083706 (2005); http://dx.doi.org/10.1063/1.2112180 (5 pages) | Cited 4 times

Online Publication Date: 21 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Space-charge waves (trap recharging waves) and the effect of spatial rectification of space-charge waves have been investigated in single crystals of 4H-SiC polytype. The relevant experimental dependencies have been found to be in quite good quantitative agreement with the theory of space-charge waves. The following parameters of the samples studied were determined: μτ = (7.4±0.8)×10−7 cm2/V, τM = (5.3±0.6)×10−4 s, and Neff = (5±1)×1013 cm−3.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.80.Jc Other crystalline inorganic semiconductors

Ultraviolet-illumination-enhanced photoluminescence effect in zinc oxide thin films

Chunming Jin, Ashutosh Tiwari, and Roger J. Narayan

J. Appl. Phys. 98, 083707 (2005); http://dx.doi.org/10.1063/1.2108156 (7 pages) | Cited 15 times

Online Publication Date: 25 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report an enhancement effect of ultraviolet illumination on the photoluminescence intensities of zinc oxide thin films. Large-grain 〈0001〉-textured zinc oxide thin films were deposited on amorphous-fused silica substrates using pulsed laser deposition. We found that the intensities of excitonic emission and green-band emission increased with ultraviolet light exposure time until a maximum value was achieved. We attribute this ultraviolet radiation enhancement effect to oxygen desorption on the surface of the zinc oxide thin film. We have proposed a phenomenological model to explain this interesting photoluminescence behavior.
Show PACS
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors
71.35.-y Excitons and related phenomena

Generalized models of the spectral response of the voltage for the extraction of recombination parameters in silicon devices

Helmut Mäckel and Andrés Cuevas

J. Appl. Phys. 98, 083708 (2005); http://dx.doi.org/10.1063/1.2115094 (9 pages) | Cited 1 time

Online Publication Date: 26 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Analytical models of the spectral response of the voltage of silicon devices have been generalized using the concept of the internal quantum efficiency of the semiconductor. This allows the extension of models used in the analysis of the internal quantum efficiency to the spectral response of the voltage. Existing models for the spectral response of the voltage that are largely employed in the surface photovoltage technique are shown to be special cases that approximate the internal quantum efficiency. A more sophisticated model of the internal quantum efficiency, the model of Isenberg, and a model that allows the analysis of the internal quantum efficiency of rear-illuminated devices have been adapted to the spectral response of the voltage. This paves the way to analyze solar cells, Schottky devices, or chemically treated silicon wafers independently of the light intensity and using front or rear illumination. The models have been validated by comparing the analysis of the spectral response of the short-circuit current and the open-circuit voltage with computer simulations for a wide range of solar cells. The model of Isenberg has been found to give in general the best prediction of the recombination parameters for both the spectral photocurrent and photovoltage. The analysis of the spectral response of the voltage can often unveil the surface recombination rate where the spectral photovoltage fails to produce any output. The measurement of rear-junction cells showed that the surface recombination rate can be predicted equally well with either method.
Show PACS
73.25.+i Surface conductivity and carrier phenomena
84.60.Jt Photoelectric conversion
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.40.+w Photoconduction and photovoltaic effects

Osmium impurity-related deep levels in n-type GaAs

A. Majid, M. Zafar Iqbal, A. Dadgar, and D. Bimberg

J. Appl. Phys. 98, 083709 (2005); http://dx.doi.org/10.1063/1.2106010 (7 pages) | Cited 1 time

Online Publication Date: 31 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The 5d transition-metal impurity, osmium, has been incorporated during the growth of n-type GaAs epitaxial layers using low-pressure metal-organic chemical-vapor deposition to characterize defect states associated with this heavy and, therefore, thermally stable dopant impurity. Deep-level transient spectroscopy has been employed to investigate the electrical characteristics of Os-related deep levels. Two prominent deep levels have been identified with Os at Ec−0.28 eV (Os1) and Ec−0.41 eV (Os2) in the upper half-band-gap of GaAs, while no Os-related level has been clearly detected in the lower half-band-gap. The detailed characteristics determined for the two levels include thermal emission rate signatures, leading to the above cited thermal activation energies, electron-capture cross sections, and their temperature dependence, measured by direct pulse-filling technique and deep-level concentrations. Further, both levels are found to exhibit a significant dependence of thermal emission rates on the junction electric field. While Os1 does not allow accurate quantitative investigations of this field dependence due to its relatively low concentration, detailed quantitative data on the field dependence of the level Os2 are reported. Analysis of these data in light of the available theoretical models allows us to conclude that Os2 is probably a substitutional donor-type defect in GaAs.
Show PACS
81.05.Ea III-V semiconductors
71.55.Eq III-V semiconductors
68.55.A- Nucleation and growth
61.72.uj III-V and II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Kk Vapor phase epitaxy; growth from vapor phase
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close