Enhanced interlayer neutral excitons and trions in trilayer van der Waals heterostructures

TL;DR

This study demonstrates enhanced interlayer neutral excitons and trions in trilayer van der Waals heterostructures, showing increased photoluminescence and tunable properties, with implications for optoelectronic device design.

Contribution

It reports the observation and analysis of interlayer excitons and trions in trilayer heterostructures, highlighting their improved optical properties and underlying mechanisms.

Findings

Higher photoluminescence quantum yields in trilayer heterostructures.

Enhanced electron-hole overlap and light absorbance confirmed by first-principles calculations.

Temperature and power dependence of exciton dynamics elucidated.

Abstract

Vertically stacked van der Waals heterostructures constitute a promising platform for providing tailored band alignment with enhanced excitonic systems. Here we report observations of neutral and charged interlayer excitons in trilayer WSe2-MoSe2-WSe2 van der Waals heterostructures and their dynamics. The addition of a WSe2 layer in the trilayer leads to significantly higher photoluminescence quantum yields and tunable spectral resonance compared to its bilayer heterostructures at cryogenic temperatures. The observed enhancement in the photoluminescence quantum yield is due to significantly larger electron-hole overlap and higher light absorbance in the trilayer heterostructure, supported via first-principle pseudopotential calculations based on spin-polarized density functional theory. We further uncover the temperature- and power-dependence, as well as time-resolved photoluminescence of the trilayer heterostructure interlayer neutral excitons and trions. Our study elucidates the prospects of manipulating light emission from interlayer excitons and designing atomic heterostructures from first-principles for optoelectronics.