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Semiconductor Heterostructures (semiconductor + heterostructure)

Distribution by Scientific Domains

Physics and Astronomy	88%

Selected Abstracts

Hybrid Inorganic/Organic Semiconductor Heterostructures with Efficient Non-Radiative Energy Transfer,

ADVANCED MATERIALS, Issue 3 2006
G. Heliotis
An inorganic/organic hybrid semiconductor heterostructure is reported, in which an InGaN quantum well is non-radiatively coupled to a semiconducting polymer overlayer (see Figure). This architecture has the potential to take advantage of the complementary attributes of the two types of semiconductor that it contains, and may lead to devices with highly efficient emission across the entire visible spectrum. [source]

Polarization of electron spin in two barrier system based on semimagnetic semiconductors

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2006
S. B. Lev
Abstract The spin-dependent tunneling of electrons through a two barrier semiconductor heterostructure with a semimagnetic layer was investigated. It was shown that the resonant level splitting in the semimagnetic well under an external magnetic field allows achieving a high level of spin polarization of the current flowing through the proposed spin filter. The dependence of the polarization depth on the parameters of the sample was calculated in the two component diffusion transport model. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Dynamics of spin interactions in diluted magnetic semiconductor heterostructures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2007
*Article first published online: 19 DEC 200, D. R. Yakovlev
Abstract This paper gives an overview of the recent studies of spin dynamics in diluted magnetic semiconductor heterostructures based on (Zn,Mn)Se and (Cd,Mn)Te. The spin dynamics is controlled by energy and spin transfer between systems of magnetic ions, lattice (phonon system) and free carriers. Spin,lattice relaxation time of the Mn spin system is a very strong function of the Mn content, it decreases by five orders of magnitude when the Mn content changes from 0.4 to 11%. Additionally this time can be tuned by the varying free carrier concentration and by the growth of heteromagnetic structures with inhomogeneous profile of Mn ions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Today's challenges in quantum dot materials research for tomorrow's quantum functional devices

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007
Richard Nötzel
Abstract Size, shape, position control, and self-organized lateral ordering of epitaxial semiconductor quantum dot (QD) arrays are demonstrated. This constitutes the prerequisite for the ultimate control of the electronic and optical properties of man-made semiconductor heterostructures at the single and multiple charge, spin, and photon level, including their quantum mechanical and electromagnetic interactions in view of applications such as quantum information processing and computing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Diamagnetic and nonlinear Zeeman shifts in spatially separated electron and hole layers of semiconductor heterostructures with disorder

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003
J. Desforges
Abstract The effect of the diamagnetic shift on the formation of excitons is investigated for double layer semiconductor systems in which electrons and holes are spatially separated. The effect of disorder due to interface roughness of the double layer structures is included in the calculation of exciton density. Numerical calculations are performed based on an effective lattice-gas model where the electron,hole system is divided into unit cells. The exciton density is calculated by using the partition function method. The effect of the nonlinear Zeeman splitting is also included in the numerical calculations. It is found that the density of the optically allowed exciton states (excitons with Sz = 0) increases under the influence of either or both the diamagnetic and the nonlinear Zeeman shifts. [source]

Effect of electron-electron interaction on the diffusion current of spin-polarized electrons

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008
Yutaka Takahashi
Abstract Electron-electron interaction modifies carrier transport in the spin-polarized system. The effects are investigated in the two-dimensional electron gas in semiconductor heterostructures. We find that the diffusion currents of spin-up and spin-down electrons are reduced, compared to the non-interacting values, by the momentum exchange between spin-up and spin-down electrons through their collisions (Spin Drag), and also by the electron energy renormalization arising from the manyparticle correlations. We numerically calculate the diffusion coefficients of spin-up and spin-down electrons separately in high-quality heterostructures of GaAs at low temperatures, including the effect of finite spin life time. Our calculations show that the diffusion coefficients are reduced down to less than half of their non-interacting values. We also find the negative diffusivity at low temperatures. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Spin and energy transfer between magnetic ions and freecarriers in diluted-magnetic semiconductor heterostructures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
D.R. Yakovlev
Abstract In this paper we give a brief overview of our studies on dynamical processes in diluted-magnetic-semiconductor heterostructures based on (Zn,Mn)Se and (Cd,Mn)Te. Presence of free carriers is an important factor which determines the energy- and spin transfer in a coupled systems of magnetic ions, lattice (the phonon system) and carriers. We report also new data on dynamical response of magnetic ions interacting with photogenerated electron-hole plasma. (Zn,Mn)Se/(Zn,Be)Se structures with relatively high Mn content of 11% provide spin-lattice relaxation time of about 20 ns, which is considerably shorter then the characterictic times of nonequilibrium phonons ranging to 1 ,s. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optical micro-characterization of group-III-nitrides: correlation of structural, electronic and optical properties

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2003
J. Christen
Abstract For a detailed understanding of complex semiconductor heterostructures and the physics of devices based on them, a systematic determination and correlation of the structural, chemical, electronic, and optical properties on a micro- or nano-scale is essential. Luminescence techniques belong to the most sensitive, non-destructive methods of semiconductor research. The combination of luminescence spectroscopy with the high spatial resolution of a scanning electron microscope, as realized by the technique of cathodoluminescence microscopy, provides a powerful tool for the optical nano-characterization of semiconductors, their heterostructures as well as their interfaces. Additional access to the local electronic and structural properties is provided by micro-Raman spectroscopy, e.g. giving insight into the local free carrier concentration and local stress. In this paper, the properties of group-III-nitrides are investigated by highly spatially and spectrally resolved cathodoluminescence microscopy in conjunction with micro-Raman spectroscopy. Complex phenomena of self-organization and their strong impact on the microscopic and nanoscopic properties of both binary and ternary nitrides are presented. As the ultimate measure of device performance, the microscopic properties of light emitting diodes are assessed under operation. Using micro-electroluminescence mapping in the optical microscope as well as in the near field detection mode of a scanning near field optical microscope, the microscopic origin of the macroscopic spectral red shift in light emitting diodes is identified. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]