ABSTRACT
Semiconductor heterostructures are used for the fabrication of optoelectronic devices. Performance of such devices is governed by their chemical morphology. The composition distribution of quantum wells and dots is influenced by kinetic growth processes which are not understood completely at present. To obtain more information about these effects, methods for composition determination with a spatial resolution at a near atomic scale are necessary. Semiconductor nanostructures containing thin layers or dots of ternary materials are used for the fabrication of optoelectronic devices such as light emitting diodes and laser diodes, whose optical properties are strongly influenced by the composition distribution that defines positions of discrete energy levels for charge carriers in quantum wells and dots. The quantitative composition evaluation of such structures with high spatial resolution is necessary, because their chemical morphology is governed by kinetic growth processes such as segregation and adatom migration that are not fully understood at present.
