Gate-Tunable Plasmon-Enhanced Photodetection in a Monolayer MoS₂ Phototransistor with Ultrahigh Photoresponsivity

Abstract

Monolayer transition metal dichalcogenides (TMDs), direct bandgap materials with an atomically thin nature, are promising materials for electronics and photonics, especially at highly scaled lateral dimensions. However, the characteristically low total absorption of photons in the monolayer TMD has become a challenge in the access to and realization of monolayer TMDbased high-performance optoelectronic functionalities and devices. Here, we demonstrate gate-tunable plasmonic phototransistors (photoFETs) that consist of monolayer molybdenum disulfide (MoS 2 ) photoFETs integrated with the two-dimensional plasmonic crystals. The plasmonic photoFET has an ultrahigh photoresponsivity of 2.7 × 10 4 AW −1 , achieving a 7.2-fold enhancement in the photocurrent compared to pristine photoFETs. This benefits predominately from the combination of the enhancement of the photon-absorption-rate via the strongly localized-electromagnetic-field and the gate-tunable plasmon-induced photocarriergeneration-rate in the monolayer MoS 2 . These results demonstrate a systematic methodology for designing ultrathin plasmonenhanced photodetectors based on monolayer TMDs for next-generation ultracompact optoelectronic devices in the trans-Moore era.

Strain‐Plasmonic Coupled Broadband Photodetector Based on Monolayer MoS2

“…[16] On the other hand, the light absorption efficiency could be improved by coupling 2D semiconductor with other materials such as plasmonic nanostructure. [17,18] For example, the integration of Au nanoparticles (NPs) on top of MoS 2 photodetectors 2D Semiconductors are promising in the development of next-generation photodetectors. However, the performances of 2D photodetectors are largely limited by their poor light absorption (due to ultrathin thickness) and small detection range (due to large bandgap).…”

“…[ 16 ] On the other hand, the light absorption efficiency could be improved by coupling 2D semiconductor with other materials such as plasmonic nanostructure. [ 17,18 ] For example, the integration of Au nanoparticles (NPs) on top of MoS 2 photodetectors exhibits over 100‐fold increase in the photocurrent compared to pristine device, and the responsivity and detectivity can reach 38.57 A W −1 and 9.89 × 10 9 Jones, respectively. [ 17 ] Similarly, the combination of Ag nanostructures with MoS 2 could also lead to high performance phototransistors with photoresponsivity up to 2.7 × 10 4 A W −1 , achieving 7.2‐fold enhancement in the photocurrent compared to the same device without nanostructures.…”

The Photodetectors Based on Lateral Monolayer MoS2/WS2 Heterojunctions

“…The high R is attributed to the suppressed photocarrier recombination in the heterostructure together with electron trapping in the MoS 2 region presumably [ 22 ]. The decreased R as the laser power density increased reveals the photogating effect in the photodetector further [ 73 ].…”

Mechanism, Material, Design, and Implementation Principle of Two-Dimensional Material Photodetectors

“…Recently, the use of field enhancement caused by surface plasmonic excitations to increase the optical response has received great attention for its potential applications in optoelectronics [114,155,156]. Local plasmons in metal nanostructures are first used in combination with graphene to achieve surface-enhanced Raman scattering [157]. The 2D materials-based plasma photodetectors lead to a significant improvement in performance by placing the plasma nanostructures near the contact point [158,159].…”