Realisation of artificial three-dimensional Ge quantum dot crystals by extreme ultraviolet interference lithography and molecular-beam epitaxy

• Applicants: Dr. Serhiy Danylyuk; Dr. Gregor Mussler
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 209979192

Quantum dots (QDs) or “artificial atoms” based on Si/Ge heterosystem are highly interesting objects with unique electronic and optical properties. Creating a dense and well-ordered array of these structures allows the realisation of a novel type of solid matter - “artificial crystals” - with energy band distributions not existing in nature. Such unique arrays can not only open up new possibilities for applications for Si/Ge based devices, but will also allow us to study fundamental questions of quantum tunnelling in zero-dimensional systems, Coulomb blockade effects and photon-electron-phonon interactions in these highly relevant materials. This project deals with the realisation of artificial three-dimensional Ge quantum dot crystals (QDCs) fabricated by means of extreme ultraviolet interference lithography (XIL) and molecular–beam epitaxy (MBE). In contrast to synchrotron-based XIL setups, we will harness a flexible stand-alone XIL system, developed at RWTH Aachen, which will allow to explore the fabrication of templated substrates in a broad wavelength range with a variety of methods targeting ultra-high resolution and density. By combining the expertise of RWTH Aachen to realise highly-dense XIL-patterned substrates with the competence of FZJ in MBE growth of Ge QDs, we aim at realizing Ge QDCs with unparalleled small lateral periodicities and substantially modified optical and transport properties compared to state-of-the art QDCs.

• DFG Programme: Research Grants