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 Feb 2006

Volume 99, Issue 4, Articles (04xxxx)

Return to All Sections
back to top
RSS Feeds

Spin-polarized transport in one-dimensional waveguide structures with spatially periodic electric fields

L. G. Wang, Kai Chang, and K. S. Chan

J. Appl. Phys. 99, 043701 (2006); http://dx.doi.org/10.1063/1.2170782 (3 pages) | Cited 10 times

Online Publication Date: 16 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate theoretically spin-polarized transport in a one-dimensional waveguide structure under spatially periodic electric fields. Strong spin-polarized current can be obtained by tuning the external electric fields. It is interesting to find that the spin-dependent transmissions exhibit gaps at various electron momenta and/or gate lengths, and the gap width increases with increasing the strength of the Rashba effect. The strong spin-polarized current arises from the different transmission gaps of the spin-up and spin-down electrons.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
72.25.Dc Spin polarized transport in semiconductors

Electronic structure and optical properties of (ZnSe)n/(Si2)m (111) superlattices

A. Laref, S. Laref, B. Belgoumene, B. Bouhafs, A. Tadjer, and H. Aourag

J. Appl. Phys. 99, 043702 (2006); http://dx.doi.org/10.1063/1.2168240 (7 pages) | Cited 5 times

Online Publication Date: 21 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic properties of (ZnSe)n/(Si2)m (111) superlattices (SLs) are investigated theoretically in order to clarify the general features of the zone-folding and the band-mixing effects in superlattices composed of an indirect-band-gap semiconductor (Si). The detailed electronic structure of (ZnSe)n/(Si2)m (111) SLs are studied with the range n = m = 10–16, giving special attention to the role of the interface states at the Zn–Si and Se–Si polar interfaces. The presence of the electric field in the SL is totally ignored, i.e., “the zero-field model.” The degeneracy of the energy minima of the conduction band at the M point in the zinc-blende-type bulk material cannot be lifted by the zone-folding effects alone. The band-mixing effect through the interfaces between the two constituent materials plays an important role in determining the overall band lineup throughout the entire Brillouin zone. The states at the conduction- and valence-band edges are confined two dimensionally in the Si layers. Furthermore, we have found two interface bands in the lower and upper regions of the gap. The states of the lower interface band are located at the Zn–Si interface, while those of the upper interface band are located at the Se–Si interface. The energies of the interface states depend on the parameters representing the Zn–Si and Se–Si bond lengths and the valence-band discontinuity between ZnSe and Si, but the interface states do not disappear from the gap with reasonable choices of the parameters. The electronic structure of the superlattice turns out to be quite sensitive to the combination of the well and barrier layer thicknesses. This sensitivity suggests the possibility of designing suitable band structures for device applications. Furthermore, the absorption spectra of the superlattices are calculated and are found to be quite different from those of bulk ZnSe and Si but fairly close to their average. The electronic and optical properties suggest that superlattices composed of indirect-band-gap semiconductors offer great potential for application to optical devices.
Show PACS
73.20.At Surface states, band structure, electron density of states
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
71.20.Nr Semiconductor compounds

Roles of microcrystalline silicon p layer as seed, window, and doping layers for microcrystalline silicon p‐i‐n solar cells

Takashi Fujibayashi and Michio Kondo

J. Appl. Phys. 99, 043703 (2006); http://dx.doi.org/10.1063/1.2173042 (4 pages) | Cited 9 times

Online Publication Date: 22 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The roles of the hydrogenated microcrystalline silicon (μc‐Si:H) p layer in the μc‐Si:H p‐i‐n solar cell fabricated by plasma-enhanced vapor deposition are determined through evaluation of the photovoltaic characteristics of solar cells fabricated by varying the deposition time of p layer. Mechanisms of p-layer growth are analyzed with in situ Auger electron spectroscopy and ex situ Raman scattering spectroscopy. Each successive regime of film growth including an amorphous silicon layer, an incubation layer containing crystalline silicon nuclei, and a layer filled with conical crystalline silicon grains that evolves in the p-layer process leads to diverse changes in the crystalline development of the subsequent μc‐Si:H i layer and in the characteristics of the solar cell.
Show PACS
84.60.Jt Photoelectric conversion
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.A- Nucleation and growth
72.40.+w Photoconduction and photovoltaic effects
78.30.Am Elemental semiconductors and insulators

Switching properties of nonlinear electron-wave directional couplers

Emmanuel Paspalakis and Andreas F. Terzis

J. Appl. Phys. 99, 043704 (2006); http://dx.doi.org/10.1063/1.2172726 (4 pages) | Cited 1 time

Online Publication Date: 22 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study two types of nonlinear electron-wave directional couplers, one with constant coupling coefficient and another with a variable coupling coefficient, and present analytical and numerical results for their switching properties.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
85.35.Ds Quantum interference devices

Interdot interaction induced zero-bias maximum of the differential conductance in parallel double quantum dots

Feng Chi and Shu-Shen Li

J. Appl. Phys. 99, 043705 (2006); http://dx.doi.org/10.1063/1.2173036 (5 pages) | Cited 25 times

Online Publication Date: 23 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the equilibrium and nonequilibrium electronic transports through a double quantum dot coupled to leads in a symmetrical parallel configuration in the presence of both the inter- and the intradot Coulomb interactions. The influences of the interdot interaction and the difference between dot levels on the local density of states (LDOS) and the differential conductance are paid special attention. We find an interesting zero-bias maximum of the differential conductance induced by the interdot interaction, which can be interpreted in terms of the LDOS of the two dots. Due to the presence of the interdot interaction, the LDOS peaks around the dot levels εi are split, and as a result, the most active energy level which supports the transport is shifted near to the Fermi level of the leads in the equilibrium situation.
Show PACS
73.63.Kv Quantum dots
73.21.La Quantum dots
73.20.At Surface states, band structure, electron density of states

Accessible information from molecular-scale volumes in electronic systems: Fundamental physical limits

Neal G. Anderson

J. Appl. Phys. 99, 043706 (2006); http://dx.doi.org/10.1063/1.2173682 (9 pages) | Cited 2 times

Online Publication Date: 28 February 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We consider fundamental limits on accessible information from molecular-scale volumes in electronic systems. Our approach is based on a quantitative measure—the volume accessible information—which we define as the Shannon mutual information associated with the best possible quantum measurement that can access a system through a specified readout volume. Specifically, we obtain a general expression for an upper bound on the volume accessible information that depends only on the manner in which information is encoded in electron states and specification of the readout volume. This bound is obtained within a tight-binding framework for simplicity and compatibility with atomistic descriptions of molecular-scale electronic systems. As an illustration, we study the volume accessible information bound for measurements accessing finite segments of long polyparaphenylene (PPP) molecules with binary information encoded in the states of electrons in the lowest unoccupied molecular orbital band. Evaluation of this bound reveals severe limits on the amount of information accessible from measurements on short PPP chain segments, where the state distinguishability required for reliable information extraction is diminished.
Show PACS
85.65.+h Molecular electronic devices
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close