相关论文: Deciphering exciton-generation processes in quantu…
The optical spectra of CdSe nanocrystals up to 55 A in diameter are analyzed in a wide range of energies from the fine structure of the low-energy excitations to the so-called high-energy transitions. We apply a symmetry-based method in two…
Excitons are two-particle correlated bound states that are formed due to Coulomb interaction between single-particle holes and electrons. In the solid-state, cooperative interactions with surrounding quasiparticles can strongly tailor the…
We theoretically investigate the scenario of a semiconductor quantum well in a microcavity, where the band structure is arranged such that optically excited electron-hole pairs cannot form Coulomb-bound excitonic states. However, it is…
Excitons, Coulomb-bound electron-hole pairs, are the fundamental excitations governing the optoelectronic properties of semiconductors. While optical signatures of excitons have been studied extensively, experimental access to the excitonic…
We study conceptional problems of a photo-electron emission (PEE) process from a free exciton in insulating crystals. In this PEE process, only the electron constituting the exciton is suddenly emitted out of the crystal, while the hole…
We report on small-cluster exact-diagonalization calculations which prove the formation of electron-hole pairs (excitons) as prerequisite for spontaneous interlayer phase coherence in bilayer systems described by the extended…
Multiple exciton generation (MEG) is a widely studied phenomenon in semiconductor nanocrystals and quantum dots wherein photo-excited carriers relax by generating additional electron-hole pairs. Here, we present the first experimental…
We theoretically study the tunnelling current of a single electron transistor (SET) under optical pumping. It found that holes in the quantum dot(QD) created by optical pumping lead to new channels for the electrons tunnelling from emitter…
Excitons in optoelectronic devices have been generated through optical excitation, external carrier injection, or employing pre-existing charges. Here, we reveal a new way to electrically generate excitons in transition metal…
In neutral dense electron-hole (e-h) systems at low temperatures, theory predicts Cooper-pair-like excitons at the Fermi energy and a BCS-like exciton condensation. Optical excitation allows creating e-h systems with the densities…
Lighting and display, relying on electric and optical down-conversion emission with sluggish power efficiency, account for >15% global electricity consumption1,2. In 2014, quantum-dot (QD) LEDs (QLEDs) with near-optimal external quantum…
Excitons are pairs of electrons and holes bound together by the Coulomb interaction. At low temperatures, excitons can form a Bose-Einstein condensate (BEC), enabling macroscopic phase coherence and superfluidity. An electronic double layer…
Cd(Se,Te) Quantum Dots (QD) in ZnSe barrier typically exhibit a very high spectral density, which precludes investigation of single dot photoluminescence. We design, grow and study individual Cd(Se,Te)/ZnSe QDs of low spectral density of…
The luminecsence of ZnSCdS-Cu phosphors of various CdS consentration (0-40%) is under investigation. The luminescence was exited by hydrogen atoms during adsorbtion of thermal energy during adsorbtion and impact recombination-heterogeneous…
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…
Optical emission from carbon nanotube transistors (CNTFETs) has recently attracted significant attention due to its potential applications. In this paper, we use a self-consistent numerical solution of the Boltzmann transport equation in…
Electrons and holes in a semiconductor form hydrogen-atom-like bound states, called excitons. At high electron-hole densities the attractive Coulomb force becomes screened and excitons can no longer exist. Bardeen-Cooper-Schrieffer theory…
The concept of \textit{optical} exciton - a photo-excited bound electron-hole pair within a crystal - is routinely used to interpret and model a wealth of excited-state phenomena in semiconductors. Beside originating sub-band gap signatures…
We describe a mechanism by which an electrical bias voltage applied across a unipolar semiconductor quantum well can drive an exciton or polariton supercurrent. The mechanism depends on the properties of electronic quasiparticles in quantum…
Solution processible colloidal quantum dots hold great promise for realizing single-photon sources embedded into scalable quantum technology platforms. However, the high-yield integration of large numbers of individually addressable…