Enhancements of thermoelectric performance utilizing self-assembled monolayers in semiconductors

We investigate the thermoelectric effect of the self-assembled monolayers (SAMs) in semiconductors (SCs). The thermoelectric performance of the SC-SAM-SC heterostructure is largely improved due to two reasons. First, the SAMs in semiconductors act as good thermal insulators. Second, the thickness of the SAMs can be smaller than one nanometer so that electrons could easily tunnel through the SAMs. As an example, we consider the GaAs-SAM-GaAs heterostructure at room temperature. The electrical conductivity, the Seebeck coefficient, and the electronic thermal conductivity as functions of donor concentration are calculated through the Boltzmann equation and the tunneling current model. The highly improved figure of merit and Seebeck coefficient demonstrate an excellent direction for fabricating high efficiency nano-thermalelectric devices.