Polarization-Controllable Transport and Optoelectronic Properties in Multiband Alignment 2D Ferroelectric Heterostructures

Understanding the dynamics of interfacial carrier transfer modulated by polarization and band alignment is crucial for optimizing the optoelectronic performance of two-dimensional (2D) ferroelectric heterostructures. In this study, we develop an analytical model to investigate exciton recombination and transport processes at the heterostructure interface under the influence of polarization with type-I, type-II, and Z-scheme band alignments. Our results demonstrate that polarization modulates the built-in electric field and interfacial barrier height, leading to approximately an order of magnitude enhancement in carrier mobility with the polarization reversal from upward to downward. Consequently, the power conversion efficiency (PCE) is improved by a factor of 1.5. We find that the Auger recombination rate plays a significant role in determining the optoelectronic properties of the Z-scheme heterostructure, whereas it can be disregarded in type-I and type-II heterostructures. Furthermore, we examined the thickness dependence of PCE and identified an optimal value at approximately 13 nm. Our results provide theoretical insight into interface recombination and transport to optimize the photovoltaic performances of ferroelectric-based nanodevices.