Published May 27, 2008 | Version v1
Miscellaneous Restricted

Analysis of self-organized In(Ga)As quantum structures with the scanning transmission electron microscope

Creators

Description

Aim of this thesis was to apply the analytical methods of the scanning transmission electron microscopy to the study of self-organized In(Ga)As quantum structures. With the imaging methods Z contrast and bright field (position resolutions in the subnanometer range) and especially with the possibilities of the quantitative chemical EELS analysis of the scanning transmission electron microscope (STEM) fundamental questions concerning morphology and chemical properties of self-organized quantum structures should be answered. By the high position resolution of the STEM among others essentail morphological and structural parameters in the growth behaviour of ''dot in a well'' (DWell) structures and of vertically correlated quantum dots (QDs) could be analyzed. For the optimization of DWell structures samples were studied, the nominal InAs-QD growth position was directedly varied within the embedding InGaAs quantum wells. The STEM offers in connection with the EELS method a large potential for the chemical analysis of quantum structures. Studied was a sample series of self-organized InGaAs/GaAs structures on GaAs substrate, the stress of which was changed by varying the Ga content of the INGaAs material between 2.4 % and 4.3 %

Availability note (English)

Available from INIS in electronic form

Abstract (German)

Ziel dieser Arbeit war es, die analytischen Methoden der Raster-Transmissionselektronenmikroskopie zur Untersuchung selbstorganisierter In(Ga)As-Quantenstrukturen anzuwenden. Mit den abbildenden Methoden Z-Kontrast und Hellfeld (Ortsaufloesungen im Subnanometerbereich) und insbesondere mit den Moeglichkeiten der quantitativen chemischen EELS-Analyse des Raster-Transmissionselektronenmikroskops (RTEMs) sollten grundsaetzliche Fragestellungen hinsichtlich der Morphologie und der chemischen Eigenschaften selbstorganisierter Quantenstrukturen beantwortet werden. Durch die hohe Ortsaufloesung des RTEMs konnten u.a. essentielle morphologische und strukturelle Parameter im Wachstumsverhalten von ''Dot in a Well''-Strukturen (DWell) und von vertikal korrelierten Quantum Dots (QDs) analysiert werden. Zur Optimierung von DWell-Strukturen wurden Proben untersucht, deren nominelle InAs-QD-Wachstumsposition innerhalb des einbettenden InGaAs-Quantum Wells (QWs) gezielt variiert wurde. Das RTEM bietet in Verbindung mit der EELS-Methode grosses Potential zur chemischen Analyse von Quantenstrukturen. Untersucht wurde eine Probenreihe selbstorganisierter InGaAs/GaAs-Strukturen auf GaAs-Substrat, deren Verspannung durch Variieren des Ga-Gehalts des InGaAs-Materials zwischen 2.4 % und 4.3 % veraendert worden ist. (orig.)

Files

Restricted

The record is publicly accessible, but files are restricted to users with access.

Additional details

Additional titles

Original title (German)
Analyse selbstorganisierter In(Ga)As-Quantenstrukturen mit dem Raster-Transmissionselektronenmikroskop

Publishing Information

Imprint Pagination
131 p.
Report number
INIS-DE--0621

INIS

Country of Publication
Germany
Country of Input or Organization
Germany
INIS RN
40042434
Subject category
S36: MATERIALS SCIENCE;
Resource subtype / Literary indicator
Thesis
Descriptors DEI
CHEMICAL COMPOSITION; CHEMICAL PROPERTIES; CRYSTAL GROWTH; ELECTRON SPECTROSCOPY; ENERGY LOSSES; GALLIUM ARSENIDES; INDIUM ARSENIDES; MORPHOLOGY; OPTIMIZATION; PARTICLE SIZE; QUANTITATIVE CHEMICAL ANALYSIS; QUANTUM DOTS; QUANTUM WELLS; SCANNING ELECTRON MICROSCOPY; STRESSES; SUBSTRATES; TRANSMISSION ELECTRON MICROSCOPY
Descriptors DEC
ARSENIC COMPOUNDS; ARSENIDES; CHEMICAL ANALYSIS; ELECTRON MICROSCOPY; GALLIUM COMPOUNDS; INDIUM COMPOUNDS; LOSSES; MICROSCOPY; NANOSTRUCTURES; PNICTIDES; SIZE; SPECTROSCOPY