Designing width-modulated Si nanowires for enhanced thermoelectric efficiency

• Monte Carlo simulations on the electron and phonon transport properties of Si nanowires modulated by constrictions.
• It is shown significant decrease of the thermal conductivity without deteriorating the electrical transport properties.
• A significant ZT enhancement compared to bulk Si is predicted in thick Si nanowires modulated by one thinner constriction.

Efficient thermoelectric energy conversion requires good electronic properties and low thermal conductivity. Width-modulated nanowires have been proposed for thermoelectric efficiency enhancement. We have used the Monte Carlo simulation technique to study the effect of width modulation on the thermoelectric transport properties of Si nanowires. We have found that it is possible to achieve significant decrease of the thermal conductivity without deteriorating the electrical transport properties. Our simulations predict enhanced thermoelectric efficiency in Si nanowires modulated by a single constriction compared to the corresponding non-modulated nanowires.

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