A study of the impact of dislocations on the thermoelectric properties of quantum wells in the Si/SiGe materials system

Jeremy R. Watling, Douglas J. Paul
2011 Journal of Applied Physics  
Thermoelectric materials generate electricity from thermal energy using the Seebeck effect to generate a voltage and an electronic current from a temperature difference across the semiconductor. High thermoelectric efficiency ZT requires a semiconductor with high electronic conductivity and low thermal conductivity. Here, we investigate the effect of scattering from threading dislocations of edge character on the thermoelectric performance of individual n and p-channel SiGe multiple quantum
more » ... ultiple quantum well structures. Our detailed physical simulations indicate that while the thermal and electrical conductivities decrease with increasing dislocation scattering/density, the Seebeck coefficient actually increases with increasing threading dislocation density above 10 6 cm À2 at room temperature, due to an increase in the entropy associated with each carrier. The collective result of these individual effects, is that the present Si-based quantum well designs can tolerate scattering by a threading dislocation density up to $10 8 cm À2 , well within the capabilities of modern growth techniques, before significant reductions in ZT due to scattering from threading dislocations is observed.
doi:10.1063/1.3665127 fatcat:ko5vmph5kjbq7ipspmxxzhoqhm