Thermoelectric efficiency of nanowires with long-range surface disorder

The electron transmission plays an important role in the design of thermoelectric devices made up from silicon nanowires. It has been shown that the transmission spectra of a rough silicon wire can be modified by introducing long-range correlations to its disordered surface. Although using the linear response theory in determining the efficiency of the possible heat engine device based on silicon nanowires is useful to point out the overall behavior with respect to the continuous incident electron energy, it says nothing about its performance as a heat engine. Actually, the energy value at which the engine optimally works should be determined from its power output. So, a nonlinear thermodynamic method is necessary to find the efficiency and power output concurrently. The efficiency at the maximum power shows that some nanowires with specific surface disorder structure are more appropriate to use as heat engines than others. The possibility of engineering the transmission of electrons in the nanowires to increase their efficiency maybe an answer to the demand of highly efficient thermoelectric semiconductor materials in future.