Low‐Temperature Thermophotovoltaic Cells by Bonding Bi₂Te₃ and Si Wafers

The thermophotovoltaic cells working under 300–500 K heat sources are fabricated by bonding Bi 2 Te 3 and Si wafers. The performance of the cells is seriously affected by the strong intrinsic excitation in Bi 2 Te 3 , which leads to the slight split of the Fermi energy level and the weak absorption in the very narrow depletion region of Bi 2 Te 3 /Si heterojunction. The valence band offset at the interface between Bi 2 Te 3 and Si, which limits the transportation of excited holes and the thickness of Bi 2 Te 3 sheet are also important to affect the performance of the cells. Although the conversion efficiency of the thermophotovoltaic cells is low, this work provides a method to fabricate Bi 2 Te 3 /Si low‐temperature thermophotovoltaic cells.