Time-Resolved Optical-Phonon Emission and Electron-Hole Relaxation Dynamics in ZnCdTe Quantum Wells and Quantum Dots

2005 ◽  
Author(s):  
P. Gilliot
Keyword(s):  
Quantum Dots ◽  
Quantum Wells ◽  
Optical Phonon ◽  
Relaxation Dynamics ◽  
Electron Hole ◽  
Time Resolved ◽  
Phonon Emission ◽  
Optical Phonon Emission

Electron–hole relaxation through optical-phonon emission in CdTe/ZnTe quantum dots

2005 ◽  
Vol 247 (1-4) ◽  
pp. 556-560
Author(s):  
S. Cronenberger ◽  
Y. Viale ◽  
O. Crégut ◽  
M. Gallart ◽  
B. Hönerlage ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Phonon ◽  
Electron Hole ◽  
Phonon Emission ◽  
Optical Phonon Emission

Carrier capture into InAs/GaAs quantum dots via multiple optical phonon emission

2001 ◽  
Vol 89 (2) ◽  
pp. 1180-1183 ◽  
Author(s):  
J. Feldmann ◽  
S. T. Cundiff ◽  
M. Arzberger ◽  
G. Böhm ◽  
G. Abstreiter
Keyword(s):  
Quantum Dots ◽  
Optical Phonon ◽  
Carrier Capture ◽  
Phonon Emission ◽  
Optical Phonon Emission

Generation of coherent terahertz radiation due to optical-phonon emission assisted transit-time resonance in quantum wells and heterolayers

2006 ◽  
Author(s):  
Pavel Shiktorov ◽  
Evgenij Starikov ◽  
Viktoras Gružinskis ◽  
Luca Varani ◽  
Christophe Palermo ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Transit Time ◽  
Terahertz Radiation ◽  
Optical Phonon ◽  
Phonon Emission ◽  
Optical Phonon Emission

scholarly journals The ultrafast onset of exciton formation in 2D semiconductors

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chiara Trovatello ◽  
Florian Katsch ◽  
Nicholas J. Borys ◽  
Malte Selig ◽  
Kaiyuan Yao ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Underlying Mechanism ◽  
Relaxation Dynamics ◽  
Electron Hole ◽  
Layer Transition ◽  
Coulombic Interactions ◽  
Formation Dynamics ◽  
Metal Dichalcogenides

Abstract The equilibrium and non-equilibrium optical properties of single-layer transition metal dichalcogenides (TMDs) are determined by strongly bound excitons. Exciton relaxation dynamics in TMDs have been extensively studied by time-domain optical spectroscopies. However, the formation dynamics of excitons following non-resonant photoexcitation of free electron-hole pairs have been challenging to directly probe because of their inherently fast timescales. Here, we use extremely short optical pulses to non-resonantly excite an electron-hole plasma and show the formation of two-dimensional excitons in single-layer MoS2 on the timescale of 30 fs via the induced changes to photo-absorption. These formation dynamics are significantly faster than in conventional 2D quantum wells and are attributed to the intense Coulombic interactions present in 2D TMDs. A theoretical model of a coherent polarization that dephases and relaxes to an incoherent exciton population reproduces the experimental dynamics on the sub-100-fs timescale and sheds light into the underlying mechanism of how the lowest-energy excitons, which are the most important for optoelectronic applications, form from higher-energy excitations. Importantly, a phonon-mediated exciton cascade from higher energy states to the ground excitonic state is found to be the rate-limiting process. These results set an ultimate timescale of the exciton formation in TMDs and elucidate the exceptionally fast physical mechanism behind this process.

Visible Photoluminescence from SI1-xGEx Quantum Wells

1993 ◽  
Vol 298 ◽  
Author(s):  
T.W. Steiner ◽  
L.C. Lenchyshyn ◽  
M.L.W. Thewalt ◽  
D.C. Houghton ◽  
J.-P. Noël ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Band Gap ◽  
Single Photon ◽  
Chemical Vapor ◽  
Band Gap Energy ◽  
Single Photon Detection ◽  
Electron Hole ◽  
Photon Detection ◽  
Time Resolved ◽  
Localized Excitons

AbstractWe have observed photoluminescence from strained SiGe quantum well layers at energies approximately equal to twice the SiGe band-gap energy. This luminescence is caused by the simultaneous recombination of two electron hole pairs yielding a single photon. Detection of luminescence at twice the band-gap has been previously used in Si to observe luminescence originating from electron-hole droplets, biexcitons, bound multiexciton complexes and polyexcitons. Time resolved spectra at twice the band-gap have been obtained from our SiGe samples prepared by molecular beam epitaxy (MIRE) as well as rapid thermal chemical vapor deposition (RTCVD). This new luminescence clearly distinguishes multiexciton or dense e-h plasma processes from single exciton processes such as bound excitons, free excitons or localized excitons, which are difficult to separate in the usual nearinfrared luminescence.

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