NUSOD Blog

Connecting Theory and Practice in Optoelectronics

Surface plasmon-enhanced photodetection in MoS2 phototransistors

weida+blog2Graphene and related 2-dimensional (2D) materials have emerged as potential building blocks for a variety of fundamental optical and electronic components, including field-effect transistors, nonvolatile memory devices, photonics devices, and phototransistors. Recently, molybdenum disulfide (MoS2) materializes as an alternative 2D nanoflake, due to its optical sensitivity, mechanical flexibility, extraordinary on/off ratio, absence of dangling bonds and compatibility to silicon CMOS processes, which may overcome the drawbacks of graphene. However, the performance of previously reported MoS2 phototransistors is limited by the low photoresponsivity which is largely due to its poor light absorption properties.

We recently observed a large photoresponse enhancement by coupling a few layers of MoS2 with plasmonic nanostructures.[1] Gold nanostructures, such as periodic nanoplates or random-distributed nanoparticles, can excite localized surface plasmonic resonance waves under illumination, thus manipulate the direction of the incident light propagation at a specific wavelength. In this manner, gold nanostructures can largely enhance light absorption efficiency as well as photoresponsivity of MoS2 phototransistors. Our further work will focus on sandwiched MSM plasmonic nanostructures (gap plasmonic), however, we are very interested in finding a collaborator on FDTD simulations.

[1] J. Miao et al., Small, 2015.

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