Funct. Mater. 2015; 22 (1): 27-33.
Peculiarities of charge carriers transport in submicron Si-Ge whiskers
1Lviv Polytechnic National University, 1 Kotliarevskyi Str., 79013 Lviv, Ukraine
2International Laboratory of High Magnetic Fields and Low Temperatures, 95 Gajowicka Str., Wroclaw 53-421, Poland
3Institute for Nuclear Research, National Academy of Sciences of Ukraine, 47 Prospect Nauky, 03680 Kyiv,Ukraine
The paper presents an analysis of impact of charge carriers transport mechanisms on the thermoelectric properties of Si-Ge submicron whiskers. Based on the resistance temperature dependences the value of activation energy for conduction submicron designs was estimated and compared with the ones for micron-scale crystals. It is shown that the activation energy of ground state ε1 of boron impurity for the Si-Ge whiskers with a diameter of 200 nm is 29.6 meV, which is typical for the bulk materials, whereas ε2 was 3.2 meV. It is suggested that the unusual high value of ε2 caused by inhomogeneous stress at the interface between the core and nanoporous shell of the submicron whisker due to their lattice mismatch. This effect can be used to create gauges with a thermoelectric principle of operation for cryogenic temperatures.
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