ENHANCEMENT OF THERMOELECTRIC POWER FACTOR BY A SILICON SPACER IN MODULATION-DOPED Si-HMS-Si

Abstract

The introduction of an un-doped silicon layer (spacer) enhances significantly the thermoelectric power factor in modulation-doped Si(Al)-MnSi1.7-Si(Al) sandwich structure. This un-doped silicon layer is inserted between the MnSi1.7 (HMS) and Al -doped silicon layers. With a proper spacer thickness, the electrical resistivity decreases sharply and is weakly dependent on temperature from 300 K to 683 K. As a result, the thermoelectric power factor can reach 0.973 × 10-3 W/m-K2 at 683 K, which is about ten times larger than that of an ordinary MnSi1.7 film without modulation doping.