Superlattices based on van der Waals 2D materials

TL;DR

This paper reviews the current state and fabrication methods of superlattices based on van der Waals 2D materials, highlighting their potential for novel quantum phenomena and diverse applications.

Contribution

It provides a comprehensive overview of 2D materials-based superlattices, detailing fabrication techniques and potential applications, advancing understanding in this emerging field.

Findings

Various fabrication methods for 2D superlattices are summarized.

Interlayer interactions can be tuned to modify properties.

Potential applications include quantum devices and optoelectronics.

Abstract

Two-dimensional (2D) materials exhibit a number of improved mechanical, optical, electronic properties compared to their bulk counterparts. The absence of dangling bonds in the cleaved surfaces of these materials allows combining different 2D materials into van der Waals heterostructures to fabricate p-n junctions, photodetectors, 2D-2D ohmic contacts that show unexpected performances. These intriguing results are regularly summarized in comprehensive reviews. A strategy to tailor their properties even further and to observe novel quantum phenomena consists in the fabrication of superlattices whose unit cell is formed either by two dissimilar 2D materials or by a 2D material subjected to a periodical perturbation, each component contributing with different characteristics. Furthermore, in a 2D materials-based superlattice, the interlayer interaction between the layers mediated by van der Waals forces constitutes a key parameter to tune the global properties of the superlattice. The above-mentioned factors reflect the potential to devise countless combinations of van der Waals 2D materials based superlattices. In the present feature article, we explain in detail the state-of-the-art of 2D materials-based superlattices and we describe the different methods to fabricate them, classified as vertical stacking, intercalation with atoms or molecules, moir\'e patterning, strain engineering and lithographic design. We also aim to highlight some of the specific applications for each type of superlattices.