Twisted MoSe2 Homobilayer Behaving as a Heterobilayer

TL;DR

This study demonstrates that a twisted MoSe2 homobilayer can mimic heterobilayer behavior through an efficient energy transfer process, leading to enhanced photoluminescence and potential applications in optoelectronics.

Contribution

It introduces a method to create a twisted MoSe2 homobilayer that behaves like a heterobilayer, revealing new insights into energy transfer mechanisms without charge transfer.

Findings

Massive photoluminescence enhancement due to energy transfer

Twisted homobilayer mimics heterobilayer behavior

Charge transfer is suppressed, energy transfer dominates

Abstract

Heterostructures (HSs) formed by the transition-metal dichalcogenides (TMDCs) materials have shown great promise in next-generation optoelectronic and photonic applications. An artificially twisted HS, allows us to manipulate the optical, and electronic properties. With this work, we introduce the understanding of the complex energy transfer (ET) process governed by the dipolar interaction in a twisted molybdenum diselenide (MoSe2) homobilayer without any charge-blocking interlayer. We fabricated an unconventional homobilayer (i.e., HS) with a large twist angle by combining the chemical vapor deposition (CVD) and mechanical exfoliation (Exf.) techniques to fully exploit the lattice parameters mismatch and indirect/direct (CVD/Exf.) bandgap nature. This effectively weaken the charge transfer (CT) process and allows the ET process to take over the carrier recombination channels. We utilize a series of optical and electron spectroscopy techniques complementing by the density functional theory calculations, to describe a massive photoluminescence enhancement from the HS area due to an efficient ET process. Our results show that the electronically decoupled MoSe2 homobilayer is coupled by the ET process, mimicking a 'true' heterobilayer nature.