MBE growth of ultra small coherent Ge quantum dots in silicon for applications in nanoelectronics

Abstract

Nanostructure based on IV–IV semiconductor has attracted great attention and large interest in academic community in recent year due to its quantum effect. Among these structures, quantum dots and wires have been considered for its potential application in Si-based optoelectronic and microwave devices. This work aimed at the research of monocrystalline Ge nano-islands, nanoclusters and nanowires formation at very high density and extra small size in Si matrix by molecular beam epitaxy (MBE). Initial nucleation stages, structural and morphological transitions depending on thermodynamic and kinetic parameters of deposition will be thoroughly studied. Experimental studies are focused on atomic and molecular processes on the growth surface in the course of formation of quantum dots and wires using MBE. New data on atomic structure and evolution of Si surface with Ge nanoclusters are obtained during MBE by reflection high-energy electron diffractometry (RHEED) and scanning-tunneling microscopy (STM). Superstructure and surface morphology is found to effect on ordering of nanoclusters lateral arrangement. The possibility of reproducible technology for manufacturing small-sized ordered Ge nanocrystals ensembles in the Si epitaxial films for device application is discussed.