The tunable interface charge transfer by polarization in two dimensional polar Al2O3/MoSO heterostructures

It is crucial to understand the electronic properties of two-dimensional (2D) semiconductor heterostructures for better application in photocatalyst and nano-electronic devices. In this work, using first-principles calculations, taking quintuple-layer (QL) Al2O3 and a Janus MoSO monolayer with out-of-plane polarization as an example, we systematically study the electronic properties of QL-Al2O3/MoSO heterostructures. By changing the different polarization direction arrangements of QL-Al2O3/MoSO heterostructures, we find that the evolution of band alignment, spatial charge distribution and interface charge transfer is synergetic. Three parts are included: first, the tuning of band alignment corresponds to the tuning of the surface charge distribution of heterostructures. Second, the charge redistribution of two monolayers corresponds to the interface charge transfer of heterostructures. The charge transfer process contains the interlayer charge transfer and inner-layer charge transfer between two monolayers. Third, the unidirectional charge transfer process through the interface is driven by the inner polarization electric field. Our work not only clarifies the interface charge transfer mechanism that can be applicable to other 2D non-polar and polar heterostructures, but also provides a theoretical basis for the application of heterostructures.

Automated summary

Understanding the electronic properties of 2D semiconductor heterostructures is crucial for their application in photocatalyst and nano-electronic devices. In this study, we use first-principles calculations to systematically investigate the electronic properties of QL-Al2O3/MoSO heterostructures. We find that the evolution of band alignment, spatial charge distribution, and interface charge transfer is synergetic, and driven by the inner polarization electric field.