Zeeman Interaction in LowDimensional IIIV Semiconductor Structures
(1997) Abstract
 The Zeeman interaction in lowdimensional IIIV semiconductor nanostructures is studied.
The effective gvalue of bulk InGaAs is measured by two different spin resonance techniques. Experimental conditions were found to control the Overhauser effect, thus enabling a highly accurate determination of the gvalue, g* = 4.070 ± 0.005, being a prerequisite for theoretical modeling of lowdimensional structures.
Novel optically detected spin resonance experiments of the electron effective gvalues in quantum wells with a typeI band alignment are reported. The material systems studied are InxGa1xAs/InP and InxGa1xAs/GaAs. These technologically important systems have not been studied before due to their... (More)  The Zeeman interaction in lowdimensional IIIV semiconductor nanostructures is studied.
The effective gvalue of bulk InGaAs is measured by two different spin resonance techniques. Experimental conditions were found to control the Overhauser effect, thus enabling a highly accurate determination of the gvalue, g* = 4.070 ± 0.005, being a prerequisite for theoretical modeling of lowdimensional structures.
Novel optically detected spin resonance experiments of the electron effective gvalues in quantum wells with a typeI band alignment are reported. The material systems studied are InxGa1xAs/InP and InxGa1xAs/GaAs. These technologically important systems have not been studied before due to their large optical transition rates giving lifetimes of electrons of the order of 0.1 to 1 nanosec. This is too short for magnetic dipoleinduced spin transitions, thus the feasibility of the present spin resonance experiments is surprising. Spin transitions induced by the electric dipole operator are identified as an explanation for these experiments. The gvalues measured at the conduction bandedge are strongly dependent on quantum confinement, which can be explained by a k.p calculation using the envelope function approximation. The spin splittings are furthermore strongly anisotropic with axial symmetry. In a twodimensional system of GaAs/AlGaAs the zeromagneticfieldsplitting for kvectors higher up in the conduction band is determined by beatings in Shubnikovde Haas oscillations.
Results of magnetic field dependent photoluminescence experiments on StranskiKrastanow quantum dots, socalled artificial atoms, are presented. In InAs dots indications for level anticrossings are found. For InAs and InP dots in various surroundings the diamagnetic shifts are presented. InP dots on a GaAs surface show luminescence peaks that stem from individual excited states of electrons in the dots. Very good agreement with a novel calculation scheme taking into account the realistic pyramidal shape of the dots is found. The accurate modeling, which is based on k.p theory, is facilitated by the knowledge of the shape and size of the dots as obtained by Atomic Force Microscopy on the same samples.
Single InP quantum dots are investigated in magnetic field dependent microphotoluminescence experiments. The measurements are based on a new experimental setup using a telescope. The results indicate that theoretical modeling is at present too simple to explain the detailed and complex structure of the spectra.
InAs selfassembled dots can be placed in a controlled manner to form regular arrangements. This is facilitated by predetermining the sites where the dots nucleate during their growth using Electron Beam Lithography and wet chemical etching to pattern the substrate. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/29798
 author
 Kowalski, Bernhard ^{LU}
 supervisor
 opponent

 Prof Chen, WeiMin, Dept. of Physics and Measurement Technology, Linköping University
 organization
 publishing date
 1997
 type
 Thesis
 publication status
 published
 subject
 keywords
 optically detected spin resonance, spin resonance, effective gvalue, IIIV semiconductors, lowdimensional structures, quantum wells, quantum dots, StranskiKrastanow, photoluminescence, GaInAs, single dot Magnetoluminescence, Fysicumarkivet A:1997:Kowalski, Halvledarfysik, Semiconductory physics, GaInAsInP
 pages
 172 pages
 publisher
 Solid State Physics, Lund University
 defense location
 Hörsal B, Fysicum, Lund
 defense date
 19970116 10:15:00
 external identifiers

 other:ISRN: LUFTD2/(TFFF0048)/1172
 ISBN
 9162828037
 language
 English
 LU publication?
 yes
 id
 53d615a5744c402a8e59ccfc5a8ae70a (old id 29798)
 date added to LUP
 20160404 11:20:26
 date last changed
 20181121 21:04:12
@phdthesis{53d615a5744c402a8e59ccfc5a8ae70a, abstract = {{The Zeeman interaction in lowdimensional IIIV semiconductor nanostructures is studied.<br/><br> <br/><br> The effective gvalue of bulk InGaAs is measured by two different spin resonance techniques. Experimental conditions were found to control the Overhauser effect, thus enabling a highly accurate determination of the gvalue, g* = 4.070 ± 0.005, being a prerequisite for theoretical modeling of lowdimensional structures.<br/><br> <br/><br> Novel optically detected spin resonance experiments of the electron effective gvalues in quantum wells with a typeI band alignment are reported. The material systems studied are InxGa1xAs/InP and InxGa1xAs/GaAs. These technologically important systems have not been studied before due to their large optical transition rates giving lifetimes of electrons of the order of 0.1 to 1 nanosec. This is too short for magnetic dipoleinduced spin transitions, thus the feasibility of the present spin resonance experiments is surprising. Spin transitions induced by the electric dipole operator are identified as an explanation for these experiments. The gvalues measured at the conduction bandedge are strongly dependent on quantum confinement, which can be explained by a k.p calculation using the envelope function approximation. The spin splittings are furthermore strongly anisotropic with axial symmetry. In a twodimensional system of GaAs/AlGaAs the zeromagneticfieldsplitting for kvectors higher up in the conduction band is determined by beatings in Shubnikovde Haas oscillations.<br/><br> <br/><br> Results of magnetic field dependent photoluminescence experiments on StranskiKrastanow quantum dots, socalled artificial atoms, are presented. In InAs dots indications for level anticrossings are found. For InAs and InP dots in various surroundings the diamagnetic shifts are presented. InP dots on a GaAs surface show luminescence peaks that stem from individual excited states of electrons in the dots. Very good agreement with a novel calculation scheme taking into account the realistic pyramidal shape of the dots is found. The accurate modeling, which is based on k.p theory, is facilitated by the knowledge of the shape and size of the dots as obtained by Atomic Force Microscopy on the same samples.<br/><br> <br/><br> Single InP quantum dots are investigated in magnetic field dependent microphotoluminescence experiments. The measurements are based on a new experimental setup using a telescope. The results indicate that theoretical modeling is at present too simple to explain the detailed and complex structure of the spectra.<br/><br> <br/><br> InAs selfassembled dots can be placed in a controlled manner to form regular arrangements. This is facilitated by predetermining the sites where the dots nucleate during their growth using Electron Beam Lithography and wet chemical etching to pattern the substrate.}}, author = {{Kowalski, Bernhard}}, isbn = {{9162828037}}, keywords = {{optically detected spin resonance; spin resonance; effective gvalue; IIIV semiconductors; lowdimensional structures; quantum wells; quantum dots; StranskiKrastanow; photoluminescence; GaInAs; single dot Magnetoluminescence; Fysicumarkivet A:1997:Kowalski; Halvledarfysik; Semiconductory physics; GaInAsInP}}, language = {{eng}}, publisher = {{Solid State Physics, Lund University}}, school = {{Lund University}}, title = {{Zeeman Interaction in LowDimensional IIIV Semiconductor Structures}}, year = {{1997}}, }