Tunable electronic and thermoelectric performance in twisted bilayer blue-phosphorene-nanoribbon-based heterojunctions

In two-dimensional bilayer systems, twist-angle-dependent electronic and thermoelectric properties have garnered significant scientific interest in recent years. In this work, based on a combination of density functional theory and non-equilibrium Green’s function method, we explore the electronic and thermoelectric properties in blue-phosphorene-nanoribbon-based heterojunction (BPNRHJ) with and without blue-phosphorene-nanoribbon(BPNR) stack. Our calculations find the electronic conductance and power factor can be strongly enhanced by the BPNR stack, and their enhancements can be further observed with the twist between the layers. The main reason for this is the electronic hybridization between the layers can provide new transport channels, and the twist can modulate the strength of interlayer electronic hybridization, resulting in extremely violent fluctuations in electron transmission and hence enhanced power factor. While the phonon thermal conductance exhibits very low dependence on the layer stack and twist. Combining these factors, our results reveal that the thermoelectric performance can be greatly modulated and enhanced in twist bilayer BPNRHJ: the figure-of-merit will be over 2.5 in 4-4-ZBPNR@ZGNRAA-8:8º at 500 K.