Prof Manfred Helm, Prof Oliver G. Schmidt, Dr Rinaldo Trotta
International Conference on Superlattices, Nanostructures, and Nanodevices (ICSNN 2012)
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Citation: Nanoscale Research Letters 2014 9:506
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Coupling effects on photoluminescence of exciton states in asymmetric quantum dot molecules
We present a theoretical study of photoluminescence from exciton states in InAs/GaAs asymmetric dot pairs, where interdot coupling is reached via magnetic field in the Faraday configuration. Electronic structu...
Citation: Nanoscale Research Letters 2014 9:297 -
Fabrication of Fe-Al nanoparticles by selective oxidation of Fe-Al thin films
The possibility of a new technique for fabricating nanoparticles from thin films using selective oxidation in an atmosphere mixture of water vapor and hydrogen was investigated. Fe-5wt.%Al films were RF-sputte...
Citation: Nanoscale Research Letters 2013 8:152 -
On the generalized Hartman effect presumption in semiconductors and photonic structures
We analyze different examples to show that the so-called generalized Hartman effect is an erroneous presumption. The results obtained for electron tunneling and transmission of electromagnetic waves through su...
Citation: Nanoscale Research Letters 2013 8:145 -
Displacing, squeezing, and time evolution of quantum states for nanoelectronic circuits
The time behavior of DSN (displaced squeezed number state) for a two-dimensional electronic circuit composed of nanoscale elements is investigated using unitary transformation approach. The original Hamiltonia...
Citation: Nanoscale Research Letters 2013 8:30 -
Conductive AFM for CNT characterization
We report on and emphasize the versatility of conductive atomic force microscopy in characterizing vertically aligned carbon nanotubes (CNTs) aimed to be used in via interconnect technology. The study is condu...
Citation: Nanoscale Research Letters 2013 8:24 -
GR-FET application for high-frequency detection device
A small forbidden gap matched to low-energy photons (meV) and a quasi-Dirac electron system are both definitive characteristics of bilayer graphene (GR) that has gained it considerable interest in realizing a ...
Citation: Nanoscale Research Letters 2013 8:22 -
Transport properties of two finite armchair graphene nanoribbons
In this work, we present a theoretical study of the transport properties of two finite and parallel armchair graphene nanoribbons connected to two semi-infinite leads of the same material. Using a single Π-band t...
Citation: Nanoscale Research Letters 2013 8:1 -
Nanoscale optical and electrical characterization of horizontally aligned single-walled carbon nanotubes
During the recent years, a significant amount of research has been performed on single-walled carbon nanotubes (SWCNTs) as a channel material in thin-film transistors (Pham et al. IEEE Trans Nanotechnol 11:44–50,...
Citation: Nanoscale Research Letters 2012 7:682 -
Extraordinary terahertz absorption bands observed in micro/nanostructured Au/polystyrene sphere arrays
Terahertz (THz) time-domain spectroscopy is carried out for micro/nanostructured periodic Au/dielectric sphere arrays on Si substrate. We find that the metal-insulator transition can be achieved in THz bandwid...
Citation: Nanoscale Research Letters 2012 7:657 -
Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures
The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 ...
Citation: Nanoscale Research Letters 2012 7:656 -
Overshoot mechanism in transient excitation of THz and Gunn oscillations in wide-bandgap semiconductors
A detailed study of high-field transient and direct-current (DC) transport in GaN-based Gunn diode oscillators is carried out using the commercial simulator Sentaurus Device. Applicability of drift-diffusion (...
Citation: Nanoscale Research Letters 2012 7:647 -
Theoretical and experimental studies of (In,Ga)As/GaP quantum dots
(In,Ga)As/GaP(001) quantum dots (QDs) are grown by molecular beam epitaxy and studied both theoretically and experimentally. The electronic band structure is simulated using a combination of k·p and tight-binding...
Citation: Nanoscale Research Letters 2012 7:643 -
In situ-prepared composite materials of PEDOT: PSS buffer layer-metal nanoparticles and their application to organic solar cells
We report an enhancement in the efficiency of organic solar cells via the incorporation of gold (Au) or silver (Ag) nanoparticles (NPs) in the hole-transporting buffer layer of poly(3,4-ethylenedioxythiophene)...
Citation: Nanoscale Research Letters 2012 7:641 -
Electron transport in a GaPSb film
We have performed transport measurements on a gallium phosphide antimonide (GaPSb) film grown on GaAs. At low temperatures (T), transport is governed by three-dimensional Mott variable range hopping (VRH) due to ...
Citation: Nanoscale Research Letters 2012 7:640 -
In situ-grown hexagonal silicon nanocrystals in silicon carbide-based films
Silicon nanocrystals (Si-NCs) were grown in situ in carbide-based film using a plasma-enhanced chemical vapor deposition method. High-resolution transmission electron microscopy indicates that these nanocrystalli...
Citation: Nanoscale Research Letters 2012 7:634 -
Dilute nitride and GaAs n-i-p-i solar cells
We demonstrate for the first time the operation of GaInNAs and GaAs n-i-p-i doping solar cells with ion-implanted selective contacts. Multiple layers of alternate doping are grown by molecular beam epitaxy to ...
Citation: Nanoscale Research Letters 2012 7:631 -
Plasmonic enhancements of photoluminescence in hybrid Si nanostructures with Au fabricated by fully top-down lithography
The authors study plasmonic enhancements of photoluminescence (PL) in Si nanodisk (ND) arrays hybridized with nanostructures such as nanoplates of Au, where these hybrid nanostructures are fabricated by fully ...
Citation: Nanoscale Research Letters 2012 7:629 -
3D modeling of dual-gate FinFET
The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety ...
Citation: Nanoscale Research Letters 2012 7:625 -
A study of photomodulated reflectance on staircase-like, n-doped GaAs/Al x Ga1−xAs quantum well structures
In this study, photomodulated reflectance (PR) technique was employed on two different quantum well infrared photodetector (QWIP) structures, which consist of n-doped GaAs quantum wells (QWs) between undoped Al ...
Citation: Nanoscale Research Letters 2012 7:622 -
Effects of shutter transients in molecular beam epitaxy
We have studied the effects of shutter transients (STs) in molecular beam epitaxy (MBE). Two series of samples were grown by MBE and evaluated by X-ray diffraction (XRD) and X-ray reflectivity (XRR) measuremen...
Citation: Nanoscale Research Letters 2012 7:620 -
Growth kinetics of MPS-capped CdS quantum dots in self-assembled thin films
For this study, we prepared colloidal CdS quantum dots using 3-mercaptopropyltrimethoxysilane as capping agent. Colloidal CdS quantum dots were directly deposited on glass substrates by a spin-coating process....
Citation: Nanoscale Research Letters 2012 7:610 -
Polarized photoreflectance and photoluminescence spectroscopy of InGaAs/GaAs quantum rods grown with As2 and As4 sources
We report photoreflectance (PR) and photoluminescence (PL) investigations of the electronic and polarization properties of different aspect ratio (height/diameter) InGaAs quantum rods (QRs) embedded in InGaAs ...
Citation: Nanoscale Research Letters 2012 7:609 -
Theoretical luminescence spectra in p-type superlattices based on InGaAsN
Citation: Nanoscale Research Letters 2012 7:607 -
Effects of an intense, high-frequency laser field on bound states in Ga1 − xIn x N y As1 − y/GaAs double quantum well
Within the envelope function approach and the effective-mass approximation, we have investigated theoretically the effect of an intense, high-frequency laser field on the bound states in a Ga x ...
Citation: Nanoscale Research Letters 2012 7:606 -
Morphological evolution of Ge/Si(001) quantum dot rings formed at the rim of wet-etched pits
We demonstrate the formation of Ge quantum dots in ring-like arrangements around predefined {111}-faceted pits in the Si(001) substrate. We report on the complex morphological evolution of the single quantum d...
Citation: Nanoscale Research Letters 2012 7:601 -
Moving gapless indirect excitons in monolayer graphene
The existence of moving indirect excitons in monolayer graphene is theoretically evidenced in the envelope-function approximation. The excitons are formed from electrons and holes near the opposite conic point...
Citation: Nanoscale Research Letters 2012 7:599 -
Temperature-dependent Raman investigation of rolled up InGaAs/GaAs microtubes
Large arrays of multifunctional rolled-up semiconductors can be mass-produced with precisely controlled size and composition, making them of great technological interest for micro- and nano-scale device fabric...
Citation: Nanoscale Research Letters 2012 7:594 -
Spin injection in n-type resonant tunneling diodes
We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have o...
Citation: Nanoscale Research Letters 2012 7:592 -
Transmission electron microscope observation of organic–inorganic hybrid thin active layers of light-emitting diodes
We performed transmission electron microscope (TEM) observation of organic–inorganic hybrid thin films fabricated by the sol–gel reaction and used as the active layers of organic light-emitting diodes. The cro...
Citation: Nanoscale Research Letters 2012 7:591 -
Picosecond carrier dynamics induced by coupling of wavefunctions in a Si-nanodisk array fabricated by neutral beam etching using bio-nano-templates
The picosecond carrier dynamics in a closely packed Si-nanodisk (Si-ND) array with ultrathin potential barrier fabricated by neutral beam etching using bio-nano-templates was investigated by time-resolved phot...
Citation: Nanoscale Research Letters 2012 7:587 -
The effect of magnetic field on the impurity binding energy of shallow donor impurities in a Ga1−xIn x N y As1−y/GaAs quantum well
Using a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga1−xIn x ...
Citation: Nanoscale Research Letters 2012 7:586 -
Charge transfer magnetoexciton formation at vertically coupled quantum dots
A theoretical investigation is presented on the properties of charge transfer excitons at vertically coupled semiconductor quantum dots in the presence of electric and magnetic fields directed along the growth...
Citation: Nanoscale Research Letters 2012 7:585 -
Nanotwinning and structural phase transition in CdS quantum dots
Nanotwin structures are observed in high-resolution transmission electron microscopy studies of cubic phase CdS quantum dots in powder form by chemical co-precipitation method. The deposition of thin films of ...
Citation: Nanoscale Research Letters 2012 7:584 -
Terahertz plasmon and surface-plasmon modes in hollow nanospheres
We present a theoretical study of the electronic subband structure and collective electronic excitation associated with plasmon and surface plasmon modes in metal-based hollow nanosphere. The dependence of the...
Citation: Nanoscale Research Letters 2012 7:578 -
Acceptor formation in Mg-doped, indium-rich Ga x In1−xN: evidence for p-type conductivity
We report on the Mg-doped, indium-rich Ga x In1−xN (x < 30). In the undoped material, the intrinsic electron density is very high and as a result there is no detectable photocond...
Citation: Nanoscale Research Letters 2012 7:574 -
Lattice dynamics of Ga1−xMn x N and Ga1−xMn x As by first-principle calculations
In this work, we present theoretical results, using first-principle methods associated to the virtual crystal approximation model, for the vibrational mode frequencies of both the Ga1−xMn x ...
Citation: Nanoscale Research Letters 2012 7:573 -
Optical properties of Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays
In this study, Ni and Cu nanowire arrays and Ni/Cu superlattice nanowire arrays are fabricated using standard techniques such as electrochemical deposition of metals into porous anodic alumina oxide templates ...
Citation: Nanoscale Research Letters 2012 7:569 -
Electronic transmittance phase extracted from mesoscopic interferometers
The usual experimental set-up for measuring the wave function phase shift of electrons tunneling through a quantum dot (QD) embedded in a ring (i.e., the transmittance phase) is the so-called ‘open’ interferom...
Citation: Nanoscale Research Letters 2012 7:568 -
Initial stage growth of Ge x Si1−x layers and Ge quantum dot formation on Ge x Si1−x surface by MBE
Critical thicknesses of two-dimensional to three-dimensional growth in Ge x Si1−x layers were measured as a function of composition for different growth temperatures. In addition...
Citation: Nanoscale Research Letters 2012 7:561 -
The intensive terahertz electroluminescence induced by Bloch oscillations in SiC natural superlattices
We report on efficient terahertz (THz) emission from high-electric-field-biased SiC structures with a natural superlattice at liquid helium temperatures. The emission spectrum demonstrates a single line, the m...
Citation: Nanoscale Research Letters 2012 7:560 -
Probability of twin formation on self-catalyzed GaAs nanowires on Si substrate
We attempted to control the incorporation of twin boundaries in self-catalyzed GaAs nanowires (NWs). Self-catalyzed GaAs NWs were grown on a Si substrate under various arsenic pressures using molecular beam ep...
Citation: Nanoscale Research Letters 2012 7:558 -
Opto-structural studies of well-dispersed silicon nano-crystals grown by atom beam sputtering
Synthesis and characterization of nano-crystalline silicon grown by atom beam sputtering technique are reported. Rapid thermal annealing of the deposited films is carried out in Ar + 5% H2 atmosphere for 5 min at...
Citation: Nanoscale Research Letters 2012 7:547 -
Room temperature passive mode-locked laser based on InAs/GaAs quantum-dot superlattice
Passive mode-locking is achieved in two sectional lasers with an active layer based on superlattice formed by ten layers of quantum dots. Tunnel coupling of ten layers changes the structural polarization prope...
Citation: Nanoscale Research Letters 2012 7:545 -
Atomistic simulations of the optical absorption of type-II CdSe/ZnTe superlattices
We perform accurate tight binding simulations to design type-II short-period CdSe/ZnTe superlattices suited for photovoltaic applications. Absorption calculations demonstrate a very good agreement with optical...
Citation: Nanoscale Research Letters 2012 7:543 -
Study of the oxygen vacancy influence on magnetic properties of Fe- and Co-doped SnO2 diluted alloys
Transition-metal (TM)-doped diluted magnetic oxides (DMOs) have attracted attention from both experimental and theoretical points of view due to their potential use in spintronics towards new nanostructured de...
Citation: Nanoscale Research Letters 2012 7:540 -
Photoconductivity and photoluminescence under bias in GaInNAs/GaAs MQW p-i-n structures
The low temperature photoluminescence under bias (PLb) and the photoconductivity (PC) of a p-i-n GaInNAs/GaAs multiple quantum well sample have been investigated. Under optical excitation with photons of energ...
Citation: Nanoscale Research Letters 2012 7:539 -
Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: effects of applied electric field and hydrostatic pressure
The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric fi...
Citation: Nanoscale Research Letters 2012 7:538 -
Inelastic light scattering by 2D electron system with SO interaction
Inelastic light scattering by electrons of a two-dimensional system taking into account the Rashba spin-orbit interaction (SOI) in the conduction band is theoretically investigated. The case of resonance scatt...
Citation: Nanoscale Research Letters 2012 7:537 -
Cyclotron resonance in HgTe/CdTe-based heterostructures in high magnetic fields
Cyclotron resonance study of HgTe/CdTe-based quantum wells with both inverted and normal band structures in quantizing magnetic fields was performed. In semimetallic HgTe quantum wells with inverted band struc...
Citation: Nanoscale Research Letters 2012 7:534