Continuous Color‐Tunable Light‐Emitting Devices Based on Compositionally Graded Monolayer Transition Metal Dichalcogenide Alloys

Abstract

The diverse series of transition metal dichalcogenide (TMDC) materials has been employed in various optoelectronic applications, such as photodetectors, light‐emitting diodes, and lasers. Typically, the detection or emission range of optoelectronic devices is unique to the bandgap of the active material. Therefore, to improve the capability of these devices, extensive efforts have been devoted to tune the bandgap, such as gating, strain, and dielectric engineering. However, the controllability of these methods is severely limited (typically ≈0.1 eV). In contrast, alloying TMDCs is an effective approach that yields a composition‐dependent bandgap and enables light emissions over a wide range. In this study, a color‐tunable light‐emitting device using compositionally graded TMDC alloys is fabricated. The monolayer WS2/WSe2 alloy grown by chemical vapor deposition shows a spatial gradient in the light‐emission energy, which varies from 2.1 to 1.7 eV. This alloy is incorporated in an electrolyte‐based light‐emitting device structure that can tune the recombination zone laterally. Thus, a continuous and reversible color‐tunable light‐emitting device is successfully fabricated by controlling the light‐emitting positions. The results provide a new approach for exploring monolayer semiconductor‐based broadband optical applications.

Tungsten dichalcogenide WS2xSe2−2x films via single source precursor low-pressure CVD and their (thermo-)electric properties

“…8,9 The ability to tune the electronic performance of these materials also benefits a multitude of optoelectronic applications, including photodetectors and light-emitting diodes, which allows for the tailoring of devices for specific photoelectronic applications. 10,11 Thin-film TDMCs can be grown via various approaches, including mechanical/liquid exfoliation, 12,13 sputtering, 14 pulsed layer deposition, 15 atomic layer deposition, 7 and molecular beam epitaxy. 16 The preparation of binary WE 2 (E = S, Se) thin films is usually achieved by sulfurization or selenization of WO 3 thin films, followed by an annealing process.…”

“…8,9 The ability to tune the electronic performance of these materials also benefits a multitude of optoelectronic applications, including photodetectors and light-emitting diodes, which allows for the tailoring of devices for specific photoelectronic applications. 10,11…”

Cryo-Compatible In Situ Strain Tuning of 2D Material-Integrated Nanocavity

“…Thanks to their strong low-dimensional electronic confinement, , vdW materials exhibit unique electronic and optical characteristics. This has led to vdW material-based optoelectronic devices including classical and quantum light sources, modulators, detectors, and nonlinear optical devices. , They have additionally been extensively explored in the context of strong light–matter coupling, − where self-hybridization has been leveraged as an effective way of coupling excitons and photons. VdW materials, especially in the monolayer limit, are also particularly attractive for their integration with photonic structures, thanks to the progress in dry transfer techniques that allow for the direct placement of vdW materials on top of pre-existing photonic structures, without requiring lattice matching with the underlying substrate material. − Taking advantage of these advancements, we demonstrate cryogenic strain tuning of cavity-coupled monolayer exciton photoluminescence (PL).…”

“…Thanks to their strong low-dimensional electronic confinement, 24,25 vdW materials exhibit unique electronic and optical characteristics. This has led to vdW material-based optoelectronic devices 26 including classical 27 and quantum light sources, 28 modulators, 29 detectors, 30 and nonlinear optical devices. 31,32 They have additionally been extensively explored in the context of strong light−matter coupling, 33−35 where selfhybridization has been leveraged as an effective way of coupling excitons and photons.…”

Probing Anisotropic Deformation and Near-Infrared Emission Tuning in Thin-Layered InSe Crystal under High Pressure

“…Two-dimensional (2D) layered semiconductors have emerged as potential enablers for ultracompact electronic and optoelectronic devices due to their exotic electrical, optical, and mechanical properties. − In particular, lattice deformations of ultrathin 2D semiconductors can quite easily occur under external forces; − recently, pressure ( p ) control has been at the forefront of improving device performance, e.g., carrier mobility, emission yield and color, and Curie temperature. − Also, the atomic, magnetic, spin, and topological phase transitions have been effectively modulated, − attracting extensive interest in developing next-generation wearable sensors, nonvolatile spintronic memories, and topological quantum computers. , …”