Van der Waals epitaxy of (Bi1−<i>x</i>In<i>x</i>)2Te3 solid solutions with a broad operating temperature range for thin-film thermoelectrics

Abstract

This work examines the growth, electronic transport properties, and thermoelectric performance of metastable (Bi1−xInx)2Te3 films that have a layered structure on mica substrates. Under non-thermodynamic equilibrium growth conditions, it is possible to achieve a large indium solubility of 32.27 at. % in the Bi2Te3 lattice. The obtained (Bi1−xInx)2Te3 solid solutions exhibit n-type tunable thermoelectric characteristics with maximized Seebeck coefficient and power factor of 105.4 μV/K and 224.6 μW m−1 K−2, respectively, by tuning the indium doping level to approach the solubility limit. The thermoelectric properties of (Bi1−xInx)2Te3 are consistently stable up to 400 K and highlight their potential for thermoelectric applications in a critical near-ambient operating regime.