The physics of electron transport in bulk silicon is investigated by using a newly developed Monte Carlo simulator which improves the state-of-the-art treatment hot carrier transport. (1) full band structure semiconductor was computed an empirical-pseudopotential method. (2) A phonon dispersion curve obtained from adiabatic bond-charge model. (3) Electron-phonon scattering rigid pseudo-ion calculated rate consistent with and silicon, thus leaving no adjustable parameters such as deformation...

The impact ionization rate in silicon is numerically derived from wave functions and energy band structure based on an empirical pseudopotential method. calculated well fitted to analytical formula with a power exponent of 4.6, indicating soft threshold rate, which originates the complexity Si structure. shows strong anisotropy at low electron (ε<3 eV), while it becomes isotropic higher energy. Numerical calculation also reveals that average secondary generated carriers depends...

Magneto-photoluminescence and photoluminescence excitation (PLE) measurements of self-organized InAs/GaAs quantum dots are reported. For fields applied along the growth direction first excited-state transition exhibits a linear Zeeman splitting, consistent with between ground electron state an excited $p$-like hole $(\ensuremath{\Delta}n\ensuremath{\ne}0).$ The mass determined from splitting is in good agreement value obtained k\ensuremath{\cdot}p calculation for highly strained dots. size...

Impact ionization rate in SiO2 was numerically calculated using both pseudo-wave functions and energy band structure based on a self-consistent pseudopotential method. To avoid numerical complexity due to amorphous structure, assumed be crystalline α-quartz. The impact shows strong wave vector anisotropy near threshold regime, primary electrons existing at Γ point yield the strongest rate. It found that results are not expressed by Keldysh formula since has complex (e.g., indirect transition...

We study energy-band engineering with nitrogen delta (δ)-doping in GaAs-related quantum structures. A tight-binding calculation indicates that the band structure can be engineered by introducing one-dimensional doping profile of into GaAs. Using molecular beam epitaxy, we prepare δ-doped samples AlGaAs/GaAs wells and GaAs/δ-doped superlattice structures at growth temperature 560 °C. Photoluminescence obtained from shows a clear redshift spectral peak positions dependent on coverage. The...

Tunneling of holes through GaAs/AlAs/GaAs single-barrier structures is studied within an elastic multichannel scattering theory. The multiband nature valence bands requires us to take into account several paths tunneling between with different effective masses, and such effect interband has not been as far we know. Calculated transmission coefficients for indicate that current strongly enhanced due tunneling. We also point out affected by the phase difference amplitudes when in-channel...

The electronic band structures of GaAs/(GaAl)As superlattices under a uniform electric field along the growth axis are calculated on basis microscopic tight-binding (TB) description. Finite sets quantum wells considered in order to apply TB method system without translational symmetry. main effect appears as diagonal elements matrix, resulting modulation miniband dispersion and localization wavefunctions (Wannier-Stark effect). results found be good agreement with experimental observation by...

Dilute nitrides are novel III–V semiconductors that have been developed for photonic and electronic devices. Although they investigated, some of their characteristics not established yet. In this study, the static dielectric constant dilute was experimentally estimated from exciton binding energy. The results imply nitrogen incorporation in decreases both bandgap. This behavior is opposite to conventional semiconductors.

We present experimental and theoretical evidence for Wannier-Stark (WS) oscillations in the DC electric current through reverse-biased highly doped p-i-n GaAs diodes. The intrinsic region diode contained seven (GaAs) 5 /(AlAs) 2 multi-quantum wells. Carrying out these transport experiments at low temperatures, we found periodic WS second derivative of Zener current, which is qualitative agreement with predictions based on a realistic multiband multichannel scattering theory. These findings...

The effect of ionized impurity scattering on Stark-ladder states is theoretically studied. We derive an expression a state when the concomitant Bloch oscillation interrupted by scattering. Based single band approximation, localized are expressed as superposition time-dependent functions through path where electronic goes through. By means Monte Carlo method, we evaluate localization length in infinite superlattice that contains ions. have found power dependence electric field. Delocalization...

Laser Raman microscope measurements in asymmetric double quantum wells with coupled narrow and wide were performed to observe the nonequilibrium longitudinal-optical (LO) phonons that are generated by electrons during phonon assisted tunneling. Both Stokes anti-Stokes intensities show maxima at a certain applied voltage, where calculated subband spacing between well states is found be equal LO energy. This fact indicates population of becomes maximum when resonant scattering occurs. A strong...

Electroreflectance measurements have been carried out in order to investigate Stark-ladder transitions a GaAs (40 AA)/AlGaAs (20 AA) superlattice under various uniform electric fields, and compared with the transition energies calculated on basis of microscopic tight-binding theory. The observed electroreflectance spectra over wide range photon (1.5-2.2 eV) shift proportion an applied field. signals higher energy region (1.4-2.2 indicate existence from spin-orbit split-off band valence...

Electronic structures of short-period GaAs/AlAs superlattices in a uniform electric field along the growth axis are studied by second-neighbor tight-binding method. Minibands X-band edge AlAs show discrete energy levels, so-called Stark ladder, as do \ensuremath{\Gamma} minibands GaAs. Electric-field-induced mixing between ladder miniband and one X is found to depend strongly on indices superlattice structures. The optical transition probability valence states that enhanced due...

We study the effects of annealing on (Ga0.64,In0.36) (N0.045,As0.955) using hard X-ray photoelectron spectroscopy and absorption fine structure measurements. observed surface oxidation termination N-As bond defects caused by process. Specifically, we a characteristic chemical shift towards lower binding energies in spectra related to In. This phenomenon appears be atomic arrangement, which produces increased In-N configurations within matrix, as indicated The reduction group-III In, occurs...

The Stark-ladder transitions in a type-II (GaAs)8/(AlAs)8 superlattice are investigated under various uniform electric fields by using electroreflectance spectroscopy. spectra suggest the existence of transition from heavy-hole state Gamma valence band to electron X conduction band. Stark ladders miniband show strong mixing with miniband. experimental data measurements compared theoretical calculation based on tight-binding method, and reasonable agreement is found.

Electroreflectance measurements have been made to clarify the resonant coupling between states in an asymmetric triple quantum well structure, where structure consists of three kinds with different widths, and their widths are designed so that ground wells conduction band should be at resonance under a certain electric field. The electroreflectance spectra reveal six types optical transition, which indicate clear about 17 kV cm-1. transition energies found agree calculated results.

We theoretically investigate formation process of quantized electronic states in electromagnetic fields. By using the path-integration theory, we first follow time-evolution an state which is initially regarded as extended band state. Next, show that eigenstate field expressed a superposition electron has undergone. may regard this effect afterimage, i.e., time average over path history. This viewpoint reflects nature electrons. Landau and Stark ladders are formed consequence afterimage effect.

An electroreflectance (ER) method is proposed as a new technique to measure strain at the Si/SiO 2 interface. Measured ER spectra from interface show shifts in photon energy corresponding magnitude of surface Si. The evaluated band structures strained Si calculated an empirical pseudopotential method. Theoretical derived bands good agreement with experimental results. strains subjected various processing conditions are by comparing those ones.

The degradation of magnetic tunnel junctions (MTJs) with AlOx barrier was experimentally investigated. Constant voltage stress (CVS) measurement carried out to monitor the time evolution conductance and tunneling magnetoresistance (TMR) MTJs. gradual increase stress-induced leakage current (SILC) observed prior breakdown, following a power law function an exponent about 0.2–0.4, which is similar case ultrathin gate oxide films in MOSFETs. measured TMR for SILC suggests that spin-dependent...

We report the observation of a resonant effect Zener current through $p\ensuremath{-}i\ensuremath{-}n$ diode structure. The second derivative $I\ensuremath{-}V$ characteristics, measured with lock-in technique, shows several pronounced peaks. These peaks indicate that quasilocalized states in quantum well intrinsic region are resonance current. A calculation tunneling based on tight-binding theory good agreement our experimental results. same holds for calculated energetic positions...