The Shockley-Read-Hall rate equations determine the average carrier transitions via a single-level defect in the band gap of a nondegenerate semiconductor. In the present work the differential rate equations for multiple levels, or localized states systems, are derived from first principles. These multiple level systems comprise the multiple discrete defects system and the coupled or excited st...

Carrier relaxation processes have been investigated in GaAs/AlxGa1−xAs v-groove quantum wires (QWRs) with a large subband separation sDE.46 meVd. Signatures of inhibited carrier relaxation mechanisms are seen in temperature-dependent photoluminescence (PL) and photoluminescence-excitation measurements; we observe strong emission from the first excited state of the QWR below ,50 K. This is attri...

We report the first all-optical study of homogeneous linewidths of surface excitations by the spectral-hole-burning technique with surface-specific second-harmonic generation as a probe. Measurement of transient spectral holes induced by a 100 fs pump pulse in excitations of the surface dangling-bond states of Si(111)-(7 x 7) led to a pump-fluence-dependent homogeneous linewidth as broad as app...

This paper describes unambiguous state discrimination (USD) for a sequence of coherent states with fluctuating phase, while considering eavesdropping against differential-phase-shift quantum key distribution systems. A measurement system extracts a fraction of the incoming signal of coherent states, estimates the carrier phase from that fraction, and then conducts a USD measurement on the main ...

Charge transport in organic materials as a function of carrier concentration is investigated. An analytical model of the concentration dependent obility based on the variable hopping range theory is formulated. This model is applied to analyze the discrepancy between the experimental obilities extracted from FETs and LEDs. The result shows that an exponential density of states (DOS) is a good a...

Measurements of the carrier relaxation dynamics in low-temperature-grown GaAs have been made with a femtosecond-resolution, time-resolved pump-probe technique using a subband-gap probe-beam wavelength. The transient absorption and index of refraction changes have been analyzed using a relaxation model with up to four different excited state populations. The carrier recombination time within the...

We study an interaction of 2D quasiparticles with linear dispersion E = ±u|p| (graphene) with impurity potential. It is shown that in 1D potential well (quantum wire) there are discrete levels, corresponding to localized states, whereas in 2D well (quantum dot) there are no such states. It is found the scattering cross-section of electrons (holes) of graphene on the axially symmetric potential ...