Morphology and Chemsitry of Lateral Composition Modulations

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The objective of this project is to extend understanding of the initiation of compositional inho-mogeneities in III-V semiconductor alloy systems. The approach utilizes a number of experimen-tal methods to examine the (non)homogeneity of alloy layers and lateral composition modulation in multilayers. A tool central to the investigation is a combined MBE-STM chamber to examine the atomic scale structure of clustering in alloy layers and lateral composition modulation in mul-tilayers. This information will feedback into the growth process and allow perfecting the assem-bly of the phase-separated regions. Specific goals are: To develop a quantitative understanding of the connections between surface reconstruction, strain, and local alloy composition for InGaAs; To determine experimentally the initiation mechanisms of spontaneous lateral composition modulation and how it relates to surface features and the local variations in alloy composition; To form self assembled arrays in InGaSbAs alloys; To establish empirically the degree of self-assembly that can be achieved using patterned substrates. The research is expected to have significant impact on basic physical understanding of alloy for-mation and origins of compositional inhomogeneities in III-V compound semiconductor material systems. The results will be applied to eliminate compositional nonuniformities within device layers. Additionally, the research forms the basis to design compositional variations in semicon-ductor thin films and exploit the novel properties arising from their nanometer-size scale struc-ture, such as low threshold lasers. %%% The project addresses fundamental research issues associated with electronic/photonic materials having technological relevance and emphasizes the integration of research and education. The project promotes teaching, training, and learning of all levels of scientific mastery, from post Ph.D. researchers, to graduate students, nontraditional undergraduates, and middle-school girls, including researchers from Primarily Undergraduate Institutions (University of Michigan-Flint). The project will also improve the research and education infrastructure in Michigan. It has al-ready established a track record for including members from underrepresented groups, including women, African Americans, and Hispanics. The PIs will continue to seek diversity in building their research team. ***