The potential of 2D transition metal-dichalcogenides for novel on-chip photonic devices

date: 04.01.2022

category: Sporočila za javnost

 

Researcher dr. Daniele Vella in collaboration with researchers from National University of Singapore has published an article In-Plane Field-Driven Excitonic Electro-Optic Modulation in Monolayer Semiconductor in journal Advanced Optical Materials (IF = 9.926). The article highlights the potential of 2D “transition metal-dichalcogenides” (TMDs) for novel on-chip photonic devices.

2D semiconductors are attractive candidates for on-chip electro-optic modulators due to their ease of integration and rich exciton-mediated phenomena. While electrostatic doping and out-of-plane field effect have been extensively studied, in-plane field-induced phenomena remain largely unexplored. Here electro-optic response of monolayer WSe2 subject to modulating in-plane electric fields probed by electroabsorption and electroreflectance spectroscopy is reported (Experimental setup and device layout Fig.1).

fig1

The devices are found to exhibit spatially varying response near exciton resonance, which cannot be explained by predicted effects such as Pockels and excitonic Stark effect. It is shown that the modulation signal is dominated by exciton linewidth broadening and narrowing associated with local accumulation and depletion of free holes (Fig.2).

fig2

The field and frequency dependence of the devices is distinct from those of charge modulation devices (field effect transistor). This lateral device configuration can be operated at significantly higher frequencies, due to the intrinsically low capacitance and absence of carrier injection (Fig.3). The observed behaviour is ascribed to elastic scattering of excitons with field-driven intrinsic free carriers. Our work highlights the potential of 2D “transition metal-dichalcogenides” (TMDs) for novel on-chip photonic devices.

fig3

Link to the article: https://doi.org/10.1002/adom.202102132

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