Experimental proof-of-principle investigation of enhanced Z3DT in (001) oriented Si/Ge superlattices

An experimental proof-of-principle of an enhanced Z(3D)T (thermoelectric figure of merit) is demonstrated using (001) oriented Si/Ge superlattices. The highest value of the experimental Z(3D)T at 300 K for a (001) oriented Si(20 Angstrom)/Ge(20 Angstrom) superlattice is 0.1 using kappa = 5 Wm(-1) K-1, for the in-plane thermal conductivity, which is a factor of seven enhancement relative to the estimated value of Z(3D)T = 0.014 for bulk Si. The good agreement between experiment and theory validates our modeling approach (denoted as carrier pocket engineering) to design superlattices with enhanced values of Z(3D)T. Proposals are made to enhance the experimental values of Z(3D)T for Si/Ge superlattices even further. (C) 2000 American Institute of Physics. [S0003-6951(00)05136-6].