Characterization of SiGe Nanowire for Thermoelectric Applications
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Thermoelectric devices directly convert heat into electricity or vice versa through simple structures without moving parts. SiGe materials are promising candidates for thermoelectric energy conversion.
This study presents the electrical characterization of p- and n-type Si0.53Ge0.47 alloy nanowires (NWs) with an average diameter of 60 nm in the temperature range of 248 K to 473 K. The SiGe NWs were fabricated by two methods: Sidewall Transfer Lithography (STL) and conventional Iline lithography followed by Focus Ion Beam (FIB) thinning. A new approach was developed to characterize the electrical and thermal properties of the NWs.
The SiGe material was grown by Reduced Pressure Chemical Vapor Deposition (RPCVD) using SiH4 and GeH4 precursors on Silicon on Insulator substrates (SOI). These samples were then condensed to Si0.53Ge0.47 layers. Doping of layers was performed through diffusion with two different sources gas of B2H6 or PH3 at 800°C. The electrical conductivity and thermopower of the SiGe NWs, fabricated by both methods, were studied and compared. The results showed an enhancement of thermopower, electrical conductivity and power factor of SiGe NWs compared to Si NWs, revealing their potential for thermoelectric material (TE) device applications.
Place, publisher, year, edition, pages
2015. , 48 p.
IdentifiersURN: urn:nbn:se:kth:diva-187362OAI: oai:DiVA.org:kth-187362DiVA: diva2:929962
Master of Science - Nanotechnology
Toprak, Muhammet, Professor