Evolution of inter-layer coupling in artificially stacked bilayer MoS2. Issue 11 (9th October 2019)

• Record Type: Journal Article
• Authors: Sarkar, Suman; Pradeepa, H. L.; Nayak, Goutham; Marty, Laetitia; Renard, Julien; Coraux, Johann; Bendiab, Nedjma; Bouchiat, Vincent; Basu, Jaydeep K.; Bid, Aveek
• Is Part Of: Nanoscale advances. Volume 1:Issue 11(2019)
• Page Start: 4398
• Page End: 4405
• Publication Date: 2019-10-09
• Subjects: 620.5
• DOI: 10.1039/c9na00517j
• Languages: English
• ISSNs: 2516-0230

Abstract

Abstract : In this paper, we show experimentally that for van der Waals heterostructures of atomically-thin materials, the hybridization of bands of adjacent layers is possible only for ultra-clean interfaces. Abstract : In this paper, we show experimentally that for van der Waals heterostructures (vdWh) of atomically-thin materials, the hybridization of bands of adjacent layers is possible only for ultra-clean interfaces. This we achieve through a detailed experimental study of the effect of interfacial separation and adsorbate content on the photoluminescence emission and Raman spectra of ultra-thin vdWh. For vdWh with atomically-clean interfaces, we find the emergence of novel vibrational Raman-active modes whose optical signatures differ significantly from that of the constituent layers. Additionally, we find for such systems a significant modification of the photoluminescence emission spectra with the appearance of peaks whose strength and intensity directly correlate with the inter-layer coupling strength. Our ability to control the intensity of the photoluminescence emission led to the observation of detailed optical features like indirect-band peaks. Our study establishes that it is possible to engineer atomically-thin van der Waals heterostructures with desired optical properties by controlling the inter-layer spacing, and consequently the inter-layer coupling between the constituent layers.