Thermoelectric Properties of Oblique SiGe Whiskers

Authors A. Druzhinin , I. Ostrovskii1,2, N. Liakh-Kaguy1, Iu. Kogut1

1 Lviv Polytechnic National University, 12, S. Bandera St, 79013 Lviv, Ukraine

2 International Laboratory of High Magnetic Fields and Low Temperatures, 95, Gajowicka St., Wroclaw, Poland

Issue Volume 8, Year 2016, Number 2
Dates Received 15 March 2016; revised manuscript received 09 June 2016; published online 15 June 2016
Citation A. Druzhinin, I. Ostrovskii, N. Liakh-Kaguy, Iu. Kogut, J. Nano- Electron. Phys. 8 No 2, 02030 (2016)
DOI 10.21272/jnep.8(2).02030
PACS Number(s) 74.25.Fy
Keywords SiGe (5) , Whiskers (3) , Thermoelectric properties (3) , Thermal conductivity (3) , Size effect (6) .
Annotation The effects of geometric features of p-type Si1 – xGex (x = 0.01-0.05) whiskers on their thermoelectric properties have been studied. Oblique whiskers of various diameters (10-100 μm) with boron impurity concentration ranging from 1017 to 1020 cm – 3 have been studied in the temperature range of 290-390 K. The Seebeck coefficient and resistivity of SiGe whiskers increased, while thermal conductivity decreased with decreasing diameter of crystals. However, the thermoelectric figure of merit of SiGe whiskers remained low, resembling that of bulk pure silicon. The influence of dopant impurities and germanium spatial distribution on the electronic and thermal transport in Si1 – xGex whiskers was likely dominant, however, little effect of the geometry was also observed. The engineering of whiskers shape and dimensions (up to 15 % improvement of thermopower in whiskers with certain obliquity), combined with appropriate doping, would likely allow for substantial improvement of their thermoelectric performance even in bulk-like scales.

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