Contribution of radial dopant concentration to the thermoelectric properties of core-shell nanowires

We report the thermoelectric characteristics of core-shell p-type germanium nanowires (GeNWs) (lightly doped core, heavily doped shell). Overall, the thermoelectric characteristics are dominated by the heavily doped shell. Experimental data indicate that surface states produce dopant deactivation when the heavily doped shell is removed. Under this situation, the thermoelectric figure of merit is degraded. Etching the heavily doped shell resulted in a rough germanium nanowire with a thermal conductivity close to 1.1 W/m-K at 300 K, which is one of the smallest k measured for nanowires and comparable to the thermal conductivity of bulk SiO2. © 2013 American Institute of Physics.