Optical Properties of Semimagnetic Quantum Dots

2002 ◽  
Vol 737 ◽  
Author(s):  
S. Mackowski ◽  
T. A. Nguyen ◽  
H. E. Jackson ◽  
L. M. Smith ◽  
J. Kossut ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Phonon Scattering ◽  
Substrate Surface ◽  
Thermal Fluctuations ◽  
Relaxation Mechanism ◽  
Emission Lines ◽  
Optical Phonon Scattering ◽  
Magnetic Quantum Dots ◽  
Single Emission

ABSTRACTMeasurements of optical properties of epitaxially grown CdMnTe quantum dots are presented. Magnetic ions are incorporated into the structure by passivating the substrate surface with Mn prior the quantum dot deposition. As expected, the intensity of intra-Mn transition increases with the time of manganese passivation. The formation of magnetic quantum dots is evidenced by presence of single emission lines in the micro-photoluminescence spectrum. The width of single dot emission lines is much broader than observed for non-magnetic quantum dots. The broadening is caused by thermal fluctuations of magnetization in quantum dots. Resonant spectroscopy results indicate that the exciton-optical phonon scattering is the main energy relaxation mechanism in these structures. The measurements suggest that post-growth thermal processing offers the possibility of tuning the magnetic properties of these structures.

scholarly journals Improvement of InAs quantum dots optical properties in close proximity to GaAs(001) substrate surface

2008 ◽  
Vol 310 (22) ◽  
pp. 4676-4680 ◽  
Author(s):  
J. Martín-Sánchez ◽  
Y. González ◽  
P. Alonso-González ◽  
L. González
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Substrate Surface ◽  
Inas Quantum Dots ◽  
Close Proximity

Deterministic Single InGaN Quantum Dots grown on GaN Micro-Pyramid Arrays

2013 ◽  
Vol 646 ◽  
pp. 34-37
Author(s):  
Per Olof Holtz ◽  
Chih Wei Hsu ◽  
Anders Lundskog ◽  
K. Fredrik Karlsson ◽  
Urban Forsberg ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Growth Conditions ◽  
Excitation Power ◽  
Emission Lines ◽  
Degree Of Polarization ◽  
Tem Analysis ◽  
Patterned Substrate ◽  
Excitation Laser ◽  
High Degree ◽  
Single Emission

InGaN quantum dots (QDs) formed on top of GaN pyramids have been fabricated by means of selective area growth employing hot wall MOCVD. Upon regrowth of a patterned substrate, the growth will solely occur in the holes, which evolve into epitaxially grown wurtzite based pyramids. These pyramids are subsequently overgrown by a thin optically active InGaN well. The QDs are preferably nucleating at the apices of the pyramids as evidenced by the transmission electron microscopy (TEM). The emission from these QDs have been monitored by means of microphotoluminescence (μPL), in which single emission lines have been detected with a sub-meV line width. The μPL measurements undoubtedly reveal that the QDs are located in the apexes of the pyramids, since the sharp emission peaks can only be monitored as the excitation laser is focused on the apices in the µPL. It is also demonstrated that the emission energy can be changed in a controlled way by altering the growth conditions, like the growth temperature and/or composition, for the InGaN layers. The tip of the GaN pyramid is on the nm scale and can be made sharp or slightly truncated. TEM analysis combined with µPL results strongly indicate that the Stranski-Krastanow growth modepreferably is taking place at the microscopic c-plane truncation of the GaN pyramid. Single emission lines with a high degree of polarization is a common feature observed for individual QDs. This emission remains unchanged with increasing the excitation power and sample temperature. An in-plane elongated QD forming a shallow potential with an equal number of electrons and holes is proposed to explain the observed characteristics of merely a single exciton emission with a high degree of polarization.

Spin-flip relaxation via optical phonon scattering in quantum dots

2013 ◽  
Vol 114 (22) ◽  
pp. 224305
Author(s):  
Zi-Wu Wang ◽  
Lei Liu ◽  
Shu-Shen Li
Keyword(s):  
Quantum Dots ◽  
Optical Phonon ◽  
Phonon Scattering ◽  
Spin Flip ◽  
Optical Phonon Scattering
Sign in / Sign up

Export Citation Format

Share Document