Imaging of interlayer coupling in van der Waals he
Post# of 22456
Evgeny M. Alexeev, Alessandro Catanzaro, Oleksandr V. Skrypka, Alexander I. Tartakovskii
(Submitted on 23 Dec 2016)
By vertically stacking monolayer crystals of transition metal dichalcogenides (TMD) and other layered materials, a new type of heterostructures can be achieved, exhibiting novel opto-electronic properties. Such van der Waals heterostructures offer a platform for developing a new generation of atomically thin, transparent and flexible devices. The performance of these devices is primarily defined by the thickness of individual layers, as well as the coupling between them. The presence of organic residues between the atomic planes can significantly lower interlayer coupling efficiency, leading to reduced charge and energy transfer between the layers. In this paper, we demonstrate a method of monitoring interlayer coupling in TMD heterostructures through photoluminescence imaging using a bright-field optical microscope. We use the presented technique to track the changes of interlayer coupling and the emergence of interlayer excitons in TMD heterobilayers after annealing. Material and thickness sensitivity of photoluminescence imaging presented i n this work makes it a powerful tool for characterisation of van der Waals heterostructures assembled by a wide variety of methods, using combinations of TMDs and other materials obtained through mechanical or chemical exfoliation and other fabrication techniques.
https://arxiv.org/abs/1612.07969