Abnormal Seebeck Effect in Vertically Stacked 2D/2D PtSe₂/PtSe₂ Homostructure

Abstract When a thermoelectric (TE) material is deposited with a secondary TE material, the total Seebeck coefficient of the stacked layer is generally represented by a parallel conductor model. Accordingly, when TE material layers of the same thickness are stacked vertically, the total Seebeck coefficient in the transverse direction may change in a single layer. Here, an abnormal Seebeck effect in a stacked two‐dimensional (2D) PtSe₂/PtSe₂ homostructure film, i.e., an extra in‐plane Seebeck voltage is produced by wet‐transfer stacking at the interface between the PtSe₂ layers under a transverse temperature gradient is reported. This abnormal Seebeck effect is referred to as the interfacial Seebeck effect in stacked PtSe₂/PtSe₂ homostructures. This effect is attributed to the carrier‐interface interaction, and has independent characteristics in relation to carrier concentration. It is confirmed that the in‐plane Seebeck coefficient increases as the number of stacked PtSe₂ layers increase and observed a high Seebeck coefficient exceeding ≈188 µV K⁻¹ at 300 K in a four‐layer‐stacked PtSe₂/PtSe₂ homostructure.