Surface plasmon-enhanced photodetection in MoTe2 phototransistors with Au nanoparticles

An effective method to improve the photoresponse of MoTe2 phototransistors by decorating with Au nanoparticles (Au NPs) is demonstrated. The Au NPs can concentrate a strong electromagnetic field around them by localized surface plasmon resonances. As a result, the light absorption of MoTe2 films could be enhanced significantly. After optimized design with Au NPs, a more than 200 times increase in the photocurrent is observed under illumination of both 365 and 405 nm light. Furthermore, the responsivities are changed from 0.61 to 398 A/W under 365 nm light illumination and from 0.43 to 220 A/W under 405 nm light illumination after decorating Au NPs onto the MoTe2 phototransistors. These findings offer an avenue for practical applications of high performance MoTe2 optoelectronic devices in the future.