Nagoya University · Engineering
Professor Noritaka Usami's research lab specializes in the epitaxial growth and characterization of advanced semiconductor nanostructures, with a focus on SiGe quantum wires and Si-based multilayered heterostructures. The lab investigates the fundamental growth mechanisms of these materials on patterned substrates, particularly using gas-source molecular beam epitaxy and selective epitaxial techniques, to achieve precise control over nanostructure morphology and optical properties. A key research direction involves understanding the role of crystallographic orientation and grain boundary structures in defect formation during crystal growth, combining experimental analysis with finite element simulation to optimize material quality. The lab's work contributes significantly to the development of high-performance group IV semiconductor devices for nanophotonics and next-generation electronics.
Figures are computed from collected data and may differ slightly.
We report on the successful fabrication of SiGe quantum wire structures on a V-groove patterned substrate by gas-source selective epitaxial growth technique, and their optical properties. Optical anisotropy, showing the realization of luminescent SiGe layers with wire geometry, was clearly observed in electroluminescence from the SiGe layers grown inside the groove.
SiGe/Si quantum wire structures were successfully fabricated on a V-groove patterned Si substrate by using gas-source Si molecular beam epitaxy (GS-SiMBE). A cross sectional image of transmission electron microscope clarified a crescent-shaped SiGe layer at the bottom of the V-groove owing to anisotropy of the growth rate on the different crystal orientations in GS-SiMBE.
We attempted to clarify relationship between grain boundary structures in Si multicrystals and generation of dislocations during crystal growth. Systematic variation of grain boundary structures was realized by employing dendritic nucleation at the initial stage of crystal growth. Etch-pit observation revealed that the contact angle of adjacent dendrite crystals to form a grain boundary affects generation of dislocations. Experimentally observed dislocation density was found to be well correlate
Open papers in the app to read, cite, and organize with AI.
