Effect of ion-implantation-induced defects and Mg dopants on the thermoelectric properties of ScNVisa övriga samt affilieringar
2018 (Engelska)Ingår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 98, nr 20, artikel-id 205307Artikel i tidskrift (Refereegranskat) Published
Abstract [en]
For applications in energy harvesting and environmentally friendly cooling, and for power sources in remote or portable applications, it is desired to enhance the efficiency of thermoelectric materials. One strategy consists of reducing the thermal conductivity while increasing or retaining the thermoelectric power factor. An approach to achieve this is doping to enhance the Seebeck coefficient and electrical conductivity, while simultaneously introducing defects in the materials to increase phonon scattering. Here, we use Mg ion implantation to induce defects in epitaxial ScN (111) films. The films were implanted with Mg+ ions with different concentration profiles along the thickness of the film, incorporating 0.35 to 2.2 at. % of Mg in ScN. Implantation at high temperature (600 degrees C), with few defects due to the temperature, does not substantially affect the thermal conductivity compared to a reference ScN. Samples implanted at room temperature, in contrast, exhibited a reduction of the thermal conductivity by a factor of 3. The sample doped with 2.2 at. % of Mg also showed an increased power factor after implantation. This paper thus shows the effect of ion-induced defects on thermal conductivity of ScN films. High-temperature implantation allows the defects to be annealed out during implantation, while the defects are retained for room-temperature implanted samples, allowing for a drastic reduction in thermal conductivity.
Ort, förlag, år, upplaga, sidor
AMER PHYSICAL SOC , 2018. Vol. 98, nr 20, artikel-id 205307
Nationell ämneskategori
Den kondenserade materiens fysik
Identifikatorer
URN: urn:nbn:se:liu:diva-153372DOI: 10.1103/PhysRevB.98.205307ISI: 000451333100009OAI: oai:DiVA.org:liu-153372DiVA, id: diva2:1271823
Anmärkning
Funding Agencies|European Research Council under the European Community [335383]; Swedish Foundation for Strategic Research through the Future Research Leaders 5 program; Swedish Research Council [2016-03365]; Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows program; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (SFO-Mat-LiU Faculty Grant) [2009 00971]; DAE-BRNS [37(3)/14/02/2015/BRNS]
2018-12-182018-12-182019-03-22