Quantum well

About: Quantum well is a research topic. Over the lifetime, 44627 publications have been published within this topic receiving 674023 citations. The topic is also known as: QW & quantum potential well.

Exciton Condensate in Semiconductor Quantum Well Structures

Abstract: We propose that the exciton condensate may form in a well-controlled way in appropriately arranged semiconductor quantum well structures. The mean-field theory of Keldysh and Kopaev, exact in both the high density and the low density limits, is solved numerically to illustrate our proposal. The electron-hole pairing gap and the excitation spectrum of the exciton condensate are obtained. The energy scales of the condensate are substantial at higher densities. We discuss how such densities could be achieved experimentally by generating an effective pressure.

100 mW deep-ultraviolet emission from aluminium-nitride-based quantum wells pumped by an electron beam

Abstract: Researchers demonstrate the generation of deep-ultraviolet light of wavelength ∼240 nm from AlxGa1−xN/AlN quantum wells by electron beam irradiation, with an output power of 100 mW and an efficiency of ∼40%. This record-breaking power is attributed to the high crystalline quality of the quantum wells and the proper well design for electron beam pumping.

Electromagnetically Induced Transparency in Semiconductors via Biexciton Coherence

Abstract: We report an experimental demonstration and theoretical analysis of electromagnetically induced transparency in a GaAs quantum well, in which the absorption of an exciton resonance is reduced by more than twentyfold. The destructive quantum interference in this scheme is set up by a control pulse that couples to a resonance of biexcitons. These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherences.

High-power ultrafast laser diodes

Abstract: Several ultrafast optical pulse generation techniques utilizing external cavity semiconductor lasers are described. These techniques include active mode locking, passive mode locking, hybrid mode locking, and several chirp compensation techniques. Utilizing these techniques, optical pulses of 200 fs in duration with over 160 W of peak power have been generated, making these pulses both the shortest and most intense ever generated with a semiconductor injection diode laser system. These pulses have been used to study the ultrafast amplification characteristics of semiconductor lasers. The results presented reveal the nature of the effects which dominate the pulse shaping mechanisms in external cavity hybrid mode-locked diode lasers. >

Microscopic calculation of the electron-phonon interaction in quantum wells

Abstract: The electron--optical-phonon scattering rates in GaAs/AlAs quantum wells are calculated on the basis of a fully microscopic description of the phonon spectra. The results indicate the great importance of confined as well as GaAs-like and AlAs-like interface phonons. By comparing our results with those of several macroscopic models, we resolve a long-standing controversy on their ability to describe the relevant vibrations.