Effects of Piezoelectric Fields in GaInN/GaN and GaN/AlGaN Heterostructures and Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
Jin Seo Im ◽  
H. Kollmer ◽  
J. Off ◽  
A. Sohmer ◽  
F. Scholz ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantitative Model ◽  
Emission Lines ◽  
Strong Increase ◽  
Time Resolved ◽  
Double Heterostructures ◽  
Decay Times ◽  
Piezoelectric Fields ◽  
Experimental Findings ◽  
Time Resolved Photoluminescence

AbstractThe effects of piezoelectric fields on the static and dynamic optical properties of GaInN/GaN and GaN/AIGaN double heterostructures and single quantum wells are studied by time-resolved photoluminescence. We find a strong increase of the luminescence decay time of the dominating transition with well thickness by several orders of magnitude. For well thicknesses larger than about 5 nm, two emission lines with strongly differing decay times are observed, which are attributed to spatially direct and indirect transitions. Our experimental findings are consistently explained by a quantitative model based on the piezoelectric fields in strained wurtzite quantum wells.

Spontaneous and Stimulated Recombination in the Nitrides

1996 ◽  
Vol 449 ◽  
Author(s):  
A. Hangleiter ◽  
F. Scholz ◽  
V. Härle ◽  
J. S. Im ◽  
G. Frankowsky
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Optical Gain ◽  
Stimulated Emission ◽  
Time Resolved ◽  
Double Heterostructures ◽  
Bulk Gan ◽  
Photoluminescence Studies ◽  
Excitonic Effects ◽  
Time Resolved Photoluminescence

ABSTRACTBoth spontaneous and stimulated emission processes are essential ingredients for constructing a laser from the nitrides. Based on our picosecond time-resolved photoluminescence studies we show that spontaneous radiative recombination is strongly influenced by excitonic effects, both in bulk GaN and in quantum wells. Particularly in quantum wells, localization of excitons plays an important role. We have studied the optical gain spectra in GaInN/GaN and GaN/AlGaN double heterostructures and quantum wells, grown by LP-MOVPE, using the stripe excitation method. Both room temperature and low temperature measurements were performed. Based on our results, we discuss the physical mechanism of optical gain in the nitrides as well as consequences for laser operation. We show that localization or, equivalently, the formation of quantum dot like structures, governs the optical gain mechanism in the nitrides.

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 Electric Field Distribution in strained p-i-n GaN/InGaN multiple quantum well structures.

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
A.N. Cartwright ◽  
Paul M. Sweeney ◽  
Thomas Prunty ◽  
David P. Bour ◽  
Michael Kneissl
Keyword(s):  
Quantum Well ◽  
Electric Field Distribution ◽  
Theoretical Calculations ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Quantum Well Structures ◽  
Piezoelectric Field ◽  
Piezoelectric Fields ◽  
Time Resolved Photoluminescence

The presence of piezoelectric fields within p-i-n GaN/InGaN multiple quantum well structures is discussed. Time integrated and time-resolved photoluminescence measurements and theoretical calculations of the effect of these fields is presented. Furthermore, a description of how these fields influence the carrier dynamics and a discussion of how the piezoelectric field effects the design of GaN/InGaN devices is presented.

scholarly journals Photo- and cathodoluminescence investigations of piezoelectric GaN/AlGaN quantum wells

2000 ◽  
Vol 639 ◽  
Author(s):  
E.M. Goldys ◽  
M. Godlewski ◽  
M.R. Phillips ◽  
A.A. Toropov
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Depth Profiling ◽  
Multiple Quantum ◽  
Recombination Mechanism ◽  
Decay Times ◽  
Piezoelectric Fields

ABSTRACTWe have examined multiple quantum well AlGaN/GaN structures with several quantum wells of varying widths. The structures had strain-free quantum wells and strained barriers. Strong piezoelectric fields in these structures led to a large red shift of the PL emission energies and long decay times were also observed. While the peak energies could be modelled using the effective mass approximation, the calculated free exciton radiative lifetimes were much shorter than those observed in experiments, indicating an alternative recombination mechanism, tentatively attributed to localised excitons. Cathodoluminescence depth profiling revealed an unusually small penetration range of electrons suggesting that electron-hole pairs preferentially remain within the multiple quantum well region due to the existing electric fields. Spatial fluctuations of the cathodoluminescence intensity were also observed.

Evaluation of hole-spin superposition in GaAs/AlGaAs quantum wells through time-resolved photoluminescence measurements

2014 ◽  
Vol 104 (25) ◽  
pp. 252406
Author(s):  
Tetsu Ito ◽  
Hideki Gotoh ◽  
Masao Ichida ◽  
Hiroaki Ando
Keyword(s):  
Quantum Wells ◽  
Time Resolved ◽  
Time Resolved Photoluminescence
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