Theoretical analysis of thermal rectification in a bulk Si/nanoporous Si device

We present a theoretical analysis of thermal rectification in a porous Si/bulk Si device, taking into account ballistic effects in phonon-pore collisions when phonon mean free path is much longer than the radius of the pores. Starting from an approximate analytical expression for the effective thermal conductivity of porous Si, we obtain the thermal rectifying coefficient of the device as a function of porosity, pore size, temperature interval, and relative lengths of porous and bulk samples.

► Heat conductivity of porous Si depends on the pore size. ► Thermal rectification for nanoporous Si/bulk Si is predicted. ► Thermal rectifying coefficient is calculated. ► It is shown to be comparable or higher to that of systems previously considered.