Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors

TL;DR

This paper reviews the excitonic properties and optoelectronic device applications of two-dimensional transition metal dichalcogenides, highlighting their strong light-matter interactions and potential in various optical technologies.

Contribution

It provides a comprehensive overview of exciton physics and recent advancements in device applications of transition metal dichalcogenides, emphasizing their unique optical properties.

Findings

Excitons dominate optical response even at room temperature.

Versatile excitonic landscape includes bright, dark, localized, and interlayer excitons.

Progress in devices like light emitters, solar cells, and photodetectors is summarized.

Abstract

Two-dimensional group-VI transition metal dichalcogenide semiconductors, such as MoS2, WSe2 and others, exhibit strong light-matter coupling and possess direct band gaps in the infrared and visible spectral regimes, making them potentially interesting candidates for various applications in optics and optoelectronics. Here, we review their optical and optoelectronic properties with emphasis on exciton physics and devices. As excitons are tightly bound in these materials and dominate the optical response even at room-temperature, their properties are examined in depth in the first part of this article. We discuss the remarkably versatile excitonic landscape, including bright, dark, localized and interlayer excitons. In the second part, we provide an overview on the progress in optoelectronic device applications, such as electrically driven light emitters, photovoltaic solar cells, photodetectors and opto-valleytronic devices, again bearing in mind the prominent role of excitonic effects. We conclude with a brief discussion on challenges that remain to be addressed to exploit the full potential of transition metal dichalcogenide semiconductors in possible exciton-based applications.