Anomalously polarised emission from a MoS2/WS2 heterostructure. Issue 19 (1st September 2021)

• Record Type: Journal Article
• Authors: Mol, P. Riya; Barman, Prahalad Kanti; Sarma, Prasad V.; Kumar, Abhishek S.; Sahu, Satyam; Shaijumon, Manikoth M.; Kini, Rajeev N.
• Is Part Of: Nanoscale advances. Volume 3:Issue 19(2021)
• Page Start: 5676
• Page End: 5682
• Publication Date: 2021-09-01
• Subjects: 620.5
• DOI: 10.1039/d1na00462j
• Languages: English
• ISSNs: 2516-0230

Abstract

Abstract : The brightening of a dark exciton state in the MoS2 layer due to doping and charge transfer from WS2 to this dark state gives rise to circularly polarized emission, from a MoS2 /WS2 heterostructure, with helicity opposite to that of the excitation. Abstract : We report circularly polarised emission, with helicity opposite to the optical excitation, from a van der Waals heterostructure (HS) consisting of a monolayer MoS2 and three-layer WS2 . Selective excitation of the MoS2 layer confirms that this cross-polarized emission is due to the charge transfer from the WS2 layers to the MoS2 layer. We propose that the high levels of n-doping in the constituent layers due to sulphur vacancies and defects give rise to an enhanced transition rate of electrons from the k valley of WS2 to the k ′ valley of MoS2, which leads to the emission, counter polarized to the excitation. Simulations based on the rate equation model support this conclusion.