Project Details
Projekt
Experimental and theoretical investigations of the thermoelectric properties of isotropically modulated silicon multilayers
Applicants
Professor Dr. Georg Bastian; Professor Dr. Hartmut Bracht; Professor Dr. Christian Heiliger; Privatdozent Dr. Anton Plech; Professor Dr. Dietrich Wolf
Subject Area
Experimental Condensed Matter Physics
Term
from 2012 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 220581848
Nanostructured semiconductors open the opportunity to independently tailor electric and thermal conductivity by manipulation of phonon transport. Within the first funding period we have shown by means of time-domain thermometry that isotope multilayer structures consisting of bilayers of (28Si/29Si) show a reduction of heat flow from a top metal layer. Preliminary calculations confirm a reduced conductance between silicon layers of different isotopic composition. We propose to fully exploit degrees of freedom of these structures by using as well the silicon isotope 30, building aperiodic multilayer stacks and introducing lateral confinement by reactive ion etching for optimizing the transport properties and show prototypic devices with improved figure of merit. Isotopically modulated silicon multilayers represent an excellent model system, which allows both for accessing the thermal properties experimentally (time domain methods, 3ω) and performing detailed theoretical calculations (molecular dynamics as well as ab-initio calculations). At the same time the use of silicon as a thermoelectric material is highly desirable. For almost all thermoelectric applications, the costs of raw materials and the required processing technique is crucial. Thus our approach using isotopically enriched silicon might pave the way for future commercial products.
DFG Programme
Priority Programmes
