scholarly journals Time-resolved observation of ballistic acceleration of electrons in GaAs quantum wells

1992 ◽  
Vol 7 (3B) ◽  
pp. B133-B136 ◽  
Author(s):  
W Sha ◽  
T B Norris ◽  
W J Schaff ◽  
K E Meyer
Keyword(s):  
Quantum Wells ◽  
Time Resolved

Anomalous Mn Spin Resonance Detected by Time-Resolved Kerr Effect in CdMnTe Quantum Wells

2002 ◽  
Vol 190 (3) ◽  
pp. 715-718 ◽  
Author(s):  
F. Teppe ◽  
C. Camilleri ◽  
D. Scalbert ◽  
Y.G. Semenov ◽  
M. Nawrocki ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Kerr Effect ◽  
Time Resolved ◽  
Spin Resonance

Optical Study of Localized and Delocalized States in GaAsN/GaAs

2003 ◽  
Vol 798 ◽  
Author(s):  
Z. Y. Xu ◽  
X. D. Luo ◽  
X. D. Yang ◽  
P. H. Tan ◽  
C. L. Yang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Rapid Thermal Annealing ◽  
Short Pulse ◽  
Selective Excitation ◽  
Excitation Power ◽  
Pulse Excitation ◽  
Optical Study ◽  
Time Resolved ◽  
Exciton Localization ◽  
Time Resolved Photoluminescence

ABSTRACTTaking advantages of short pulse excitation and time-resolved photoluminescence (PL), we have studied the exciton localization effect in a number of GaAsN alloys and GaAsN/GaAs quantum wells (QWs). In the PL spectra, an extra transition located at the higher energy side of the commonly reported N-related emissions is observed. By measuring PL dependence on temperature and excitation power along with PL dynamics study, the new PL peak has been identified as a transition of the band edge-related recombination in dilute GaAsN alloy and delocalized transition in QWs. Using selective excitation PL we further attribute the localized emission in QWs to the excitons localized at the GaAsN/GaAs interfaces. This interface-related exciton localization could be greatly reduced by a rapid thermal annealing.

scholarly journals Enhancement of quantum efficiency in InGaN quantum wells by using superlattice interlayers and pulsed growth

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Kazimieras Nomeika ◽  
Mantas Dmukauskas ◽  
Ramūnas Aleksiejūnas ◽  
Patrik Ščajev ◽  
Saulius Miasojedovas ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Recombination Coefficient ◽  
Time Resolved ◽  
Mocvd Growth ◽  
Lower Strain ◽  
Type Contact ◽  
Ingan Quantum Wells

Enhancement of internal quantum efficiency (IQE) in InGaN quantum wells by insertion of a superlattice interlayer and applying the pulsed growth regime is investigated by a set of time-resolved optical techniques. A threefold IQE increase was achieved in the structure with the superlattice. It was ascribed to the net effect of decreased internal electrical field due to lower strain and altered carrier localization conditions. Pulsed MOCVD growth also resulted in twice higher IQE, presumably due to better control of defects in the structure. An LED (light emitting diode) structure with a top p-type contact GaN layer was manufactured by using both growth techniques with the peak IQE equal to that in the underlying quantum well structure. The linear recombination coefficient was found to gradually increase with excitation due to carrier delocalization, and the latter dependence was successfully used to fit the IQE droop.

scholarly journals Spatio-Time-Resolved Cathodoluminescence Spectroscopy Imaging: Microscopic Recombination Kinetics in Semi-Polar InGaN Quantum Wells

2010 ◽  
Vol 16 (S2) ◽  
pp. 812-813
Author(s):  
J Christen ◽  
F Bertram ◽  
S Metzner ◽  
T Wunderer ◽  
F Lipski ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Time Resolved ◽  
Cathodoluminescence Spectroscopy ◽  
Recombination Kinetics ◽  
Ingan Quantum Wells

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

Low-temperature internal quantum efficiency of GaInN/GaN quantum wells under steady-state conditions

2022 ◽  
Author(s):  
Shawutijiang Sidikejiang ◽  
Philipp Henning ◽  
Philipp Horenburg ◽  
Heiko Bremers ◽  
Uwe Rossow ◽  
...  
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Internal Quantum Efficiency ◽  
Structural Defects ◽  
Measured Intensity ◽  
Time Resolved ◽  
Absorbed Power ◽  
Radiative Losses ◽  
Effects Of Temperature ◽  
Excitation Conditions

Abstract We compare the low-temperature photoluminescence (PL) intensities of a range of GaInN/GaN quantum well (QW) structures under identical excitation conditions, mounting the samples side by side. Normalizing the measured intensity to the absorbed power density in the QWs, we find that low-temperature PL efficiencies of several samples, which show close to 100% IQE in time-resolved PL, saturate at nearly an identical value. Of course, this is strong indicative of being 100% IQE at low temperature for those efficient samples. Using the low-temperature PL efficiency as a ``Reference'', on the other hand, we observe not only the effects of temperature-independent non-radiative losses on the low-temperature IQE, but also are able to determine the IQE of arbitrary samples on an absolute scale. Furthermore, we prove the experimental results by comparing the low-temperature efficiencies of a sample with an initial 100% IQE after intentionally introducing structural defects with argon-implantation.

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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