Publication

4-Wave-Mixing Signals from Extended Exciton-States above the Mobility Edge in Gaas (Ga,Al)as Multiple-Quantum Wells

Jean-Louis Staehli
1994
Journal Articles

Abstract

We investigate the dependence of four-wave mixing response on the photon energy close to the fundamental exciton (X) resonance in GaAs quantum wells. We find that cross-polarised incident fields give rise to a non-linear signal which decays faster at energies below the X line centre than above. We show that this behaviour cannot be assigned to biexciton transitions alone but rather suggests that the delocalised X states above the mobility edge are excited off-resonantly by the laser light having slightly lower energies.

Official source

https://infoscience.epfl.ch/entities/publication/00072d0e-5846-46af-8cda-989401bf35fa

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Jean-Louis Staehli
1994
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/00072d0e-5846-46af-8cda-989401bf35fa

About this result

Related concepts (32)

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.

Quantum well

A quantum well is a potential well with only discrete energy values. The classic model used to demonstrate a quantum well is to confine particles, which were initially free to move in three dimensions, to two dimensions, by forcing them to occupy a planar region. The effects of quantum confinement take place when the quantum well thickness becomes comparable to the de Broglie wavelength of the carriers (generally electrons and holes), leading to energy levels called "energy subbands", i.e.

Exciton

An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force. It is an electrically neutral quasiparticle that exists in insulators, semiconductors and some liquids. The exciton is regarded as an elementary excitation of condensed matter that can transport energy without transporting net electric charge. An exciton can form when a material absorbs a photon of higher energy than its bandgap. This excites an electron from the valence band into the conduction band.

Related publications (32)

4-Wave-Mixing Signals from Extended Exciton-States above the Mobility Edge in Gaas (Ga,Al)as Multiple-Quantum Wells

Chat with Graph Search

Hybrid integrated photonics for coherent microwave-optical transduction

Subpicosecond thermalization of carriers in polar GaN/AlN quantum dots

Mid-Infrared Modulation of Quantum Emitters in Hexagonal Boron Nitride