The influence of fabrication adhesion temperature on the excitonic behavior of 2D MoS2/hBN heterostructures

This is the authors' abstract. We don't add key points for this paper.

Heterostructures are key components in photonic devices consisting of two-dimensional (2D) materials. Therefore, understanding the impact of their fabrication process parameters on their performances is of utmost importance. We fabricated MoS 2 /hBN heterostructures and investigated the effect of the adhesion temperature on their light emission. Raman analysis reveals that adhesion temperatures above ~ 100 ° C induce atomic modifications, manifested by redshifts of the E 2g and A 1g vibrational modes. Light-emission analysis revealed a lower emission intensity in the heterostructure than in bare MoS 2 , with a further reduction in intensity as the adhesion temperature increased. Additionally, photoluminescence (PL) analysis revealed that the A-excitons and trions dominate the light emission (jointly composing above 99% of the emission spectral weight), while the B-excitons contribution was negligible. Importantly, the adhesion temperature did not alter the charge-carrier concentration. Atomistic molecular dynamics simulation reveals that these changes result from thermal buckling induced by the thermal-expansion mismatch between the MoS 2 and hBN layers. Therefore, these insights identify the fabrication parameters that influence the light-emission characteristics of heterostructures and enable modulation of their excitonic emission, paving the way for the future development of optically engineered emitting devices.