13.06.2013 - GAST: PROF. DR. UWE KORTSHAGEN
Am 17.06.2013 hält Prof. Dr. Uwe Kortshagen von der University of Minnesota, USA, einen Vortrag über "Silicon Quantum Dots: At the Intersect of Plasmas, Semiconductors, and Device Engineering" (Einführung: Prof. Dr. Uwe Czarnetzki). Der Vortrag findet im HNB ab 12:15 Uhr im Rahmen des Physikalischen Kolloquiums statt. Interessierte sind herzlich eingeladen!
Prof. Kortshagen ist Distinguished McKnight University Professor und Department Head am Department Mechanical Engineering und leitet das.
Prof. Dr. Uwe Kortshagen
ABSTRACT: Quantum confined nanocrystals, also called quantum dots, are attractive building blocks for opto-electronic devices owing to their size-dependent optical and electronic properties. While chalcogenide semiconductor quantum dots can conveniently be synthesized with liquid phase reactions, there are concerns about the abundance of their constituent elements and their toxicity.
Covalently bonded group IV semiconductors such as silicon are both abundant and nontoxic but require approaches that provide higher synthesis temperatures. Nonthermal plasmas have emerged as the synthesis route of choice for silicon and other group IV materials, since they provide high temperatures, narrow particle size distributions, and the ability to tailor the quantum dot surface properties with a great level of control.
This presentation will discuss the synthesis of quantum confined silicon nanocrystals with a capacitively coupled low-pressure plasma approach, which enables the production of macroscopic quantities of material with excellent control over quantum dot size and crystallinity. This synthesis scheme also enables one to selectively attach surface groups to the silicon quantum dots, which allow for optical quantum yields in photo- and electro-luminescence which are unprecedented for indirect bandgap semiconductors. Finally, the presentation will focus on how the efficient light emitting properties of silicon quantum dots can be utilized in highefficiency hybrid organic/nanocrystal light emitting devices.
This work was supported by the National Science Foundation (NSF) MRSEC Program under award number DMR-0819885, NSF award ECCS-0925624, and the Center for Advanced Solar Photophysics, a Department of Energy funded Energy Frontier Research Center.