Related papers: Direct bandgap optical transitions in Si nanocryst…
The shifts of the electronic absorption spectra of GaAs and GaP semiconductor clusters are calculated using accurate pseudopotentials. In the absence of experimental data at present, these calculations provide estimates of expected spectral…
Photons do not carry sufficient momentum to induce indirect optical transitions in semiconducting materials such as silicon, necessitating the assistance of lattice phonons to conserve momentum. Compared to direct bandgap semiconductors,…
The size of the bandgap in a photonic crystal ring is typically intuitively considered to monotonically grow as the modulation amplitude of the grating increases, causing increasingly large frequency splittings between the 'dielectric' and…
Since the forward and backward waves are coupled with each other and a standing wave with no net propagation of energy is formed in the photonic bandgap, it is a commonsense of basic physics that, any kinds of effects associated with wave…
The shift of energy levels owing to broadband electromagnetic vacuum fluctuations, the Lamb shift, has been pivotal in the development of quantum electrodynamics and in understanding atomic spectra. Currently, small energy shifts in…
We consider theoretically a closed (zero-dimensional) semiconductor microcavity where confined vacuum photonic mode is coupled to electrons in valence band of the semiconductor. It is shown that vacuum-induced virtual electron transitions…
We study the dynamic electronic polarizability of a single nano-scale spherical metallic grain using quantum mechanical approach. We introduce the model for interacting electrons bound in the grain allowing us numerically to calculate the…
We study the quantum squeezing produced in self-induced transparency in a photonic crystal fiber by performing a fully quantum simulation based on the positive $P$ representation. The amplitude squeezing depends on the area of the initial…
It has been shown theoretically that strong quantum confinement regime in Si nanocrystals promotes the highly efficient simultaneous excitation of two electron-hole pairs (biexciton) by a single photon. The rate (inverse lifetime) of…
Using the FDTD method, we investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel air cylinders in a dielectric medium. The corresponding frequency band structure is computed using the standard…
The electrons in undoped graphene behave as massless Dirac fermions. Therefore graphene can serve as an unique condensed-matter laboratory for the study of various relativistic effects, including quantum electrodynamics (QED) phenomena.…
We present ultrafast optical switching experiments on 3D photonic band gap crystals. Switching the Si inverse opal is achieved by optically exciting free carriers by a two-photon process. We probe reflectivity in the frequency range of…
This study shows that the dielectric function of crystalline Si quantum wells (c-Si QW) is influenced by both carrier confinement and electron-phonon interactions. The energy shifts and lifetime broadening of the excitonic E1 direct gap…
With the development of modern nanoscience and nanotechnology, Bi1-xSbx can be synthesized into different nanoscale and nanostructured forms, including thin films, nanowires, nanotubes, nanoribbons, and many others. However, due to the…
The optical emission spectra from Ge films on Si are markedly different from their bulk Ge counterparts. Whereas bulk Ge emission is dominated by the material's indirect gap, the photoluminescence signal from Ge films is mainly associated…
We embark on investigating the magneto-optical absorption in {\em spherical} quantum dots {\em completely} confined by a harmonic potential and exposed to an applied magnetic field in the symmetric gauge. This is done within the framework…
In the recent work of Ref.\cite{Vlaic2017-bs}, it has been shown that Pb nanocrystals grown on the electron accumulation layer at the (110) surface of InAs are in the regime of Coulomb blockade. This enabled the first scanning tunneling…
We show how to compute the optical functions of Wide Parabolic Quantum Wells (WPQWs) exposed to uniform electric F applied in the growth direction, in the excitonic energy region. The effect of the coherence between the electron-hole pair…
Contrary to recent reports, we show that the electronic properties of phosphorene nanotubes are surprisingly rich and much more complex than previously assumed. We find that all phosphorene nanotubes exhibit an intricate direct-to-indirect…
A comprehensive ellipsometric study was performed on Fe$_{1-x}$Co$_{x}$Si single crystals in the spectral range from 0.01 eV to 6.2 eV. Direct and indirect band gaps of 73 meV and 10 meV, respectively, were observed in FeSi at 7 K. One of…