SANGUINETTI STEFANO

My main research activity focuses on the field of III-V semiconductor heterostructures and nanostructures for optoelectronic applications covering various aspects related to the growth, the optical characterization and the modeling. In particular semiconductor quantum nanostructure growth fundamental studies and device applications.

This activity relies on my previous experience on both experimental and theoretical research starting from the graduation and continuing during my years as Assistant Professor at the Milano-Bicocca University. My theoretical activity started with the ab-initio modeling of defects in semiconductors (with Prof. Teichler at Goettingen Univ.) and continued studying carbon-based networks with complex topology in the group of Prof. Benedek, also in collaboration with the FKF Max Plank Institute. Experimentally my attention was devoted to the study of the emission properties of semiconductor quantum nanostructures in collaboration with Nottingham University (Prof. Eaves) and NIMS-Japan (Prof. Koguchi)

In 2008, after 15-year experience in the modelling, using both ab-initio and semiempirical simulation methods, and optical characterization of the electronic properties of semiconductors, I founded a new laboratory, within the InterUniversity (Milano-Bicocca University and Politecnico di Milano) laboratory L-NESS (I'm now Vice-Director of L-NESS), for the development of innovative growth strategies for the fabrication, by Molecular Beam Epitaxy, of nanostructured III-V materials based on kinetically controlled growth processes. The approach I have adopted for the research planning is to combine, directly in the material and growth process design phase, a deep understanding of semiconductor basic growth methods, nanostructure electronic states knowledge and device design. This permit to make use of extremely innovative growth processes, to achieve basic understanding of the physical phenomena in the growth and in the structure, while directly targeting device applications. In this respect my multidisciplinary experience plays a fundamental role, allowing for an in-depth understanding of all the steps involved in the device design, from growth, to device engineering. My main achievement is the development of an innovative growth procedure, invented by NIMS labs in Japan, for quantum nanostructure formation, the Droplet Epitaxy. This growth method permits the self-assembly of nanoisland of the desired shape on virtually any substrate, included silicon.

Also thanks my discoveries and my efforts to constitute and coordinate a scientific community focused on its development, the Droplet Epitaxy gained a relevant status among nanostructure growth processes and it is now one of the best way to obtain single photon sources for quantum photonic applications. Several projects proposed, both on-going and completed (see list), are based on this innovative growth method. In particular 4PHOTON, an MSCA-ITN network, approaches the development of fundamental strategies for the implementation of innovative quantum technologies starting from Droplet Epitaxy nanostructures. More recently, I implemented kinetic controlled growth methods for the fabrication of vertical heterostructures for the integration of high quality III-V materials on Si. This is a strongly innovative approach, that permits the design of completely different device design. Two projects based on this approach are on-going, one of them an H2020-FET (microSPIRE).

My approach, combining fundamental studies with a clear application target, gained a major recognition by the community, with many invited talks in the major conference of the area (19 from 2009) and the involvement program and steering committee of the major conferences (including the International Conference of Molecular Beam Epitaxy) and the direct organization of two of them. In recognition of the relevance of my work at the international level, a joint laboratory (QuCAT), between the my laboratory at L-NESS/Milano-Bicocca University and the South China Normal University of Guangzhou, for the development quantum nanostructured InGaN materials for photocatalysis has been recently established (July 2018).