A localized surface plasmon resonance and light confinement-enhanced near-infrared light photodetector

Light manipulation is paramountly important to the fabrication of high-performance optoelectronic devices such as solar cells and photodetectors. In this study, a high-performance near-infrared light nanophotodetector (NIRPD) was fabricated based on a germanium nanoneedles array (GeNNs array) with strong light confining capability, and single-layer graphene (SLG) modified with heavily doped indium tin oxide nanoparticles (ITONPs), which were capable of inducing localized surface plasmon resonance (LSPR) under NIR irradiation. An optoelectronic study shows that after modification with ITONPs the device performance including photocurrent, responsivity and detectivity was considerably improved. In addition, the ITONPs@SLG/GeNNs array NIRPD was able to monitor fast-switching optical signals, the frequency was as high as 1MHz, with very fast response rates. Theoretical simulations based on finite-element method (FEM) revealed that the observed high performance was not only due to the strong light-confining capability of the GeNNs array, but also due to the plasmonic ITONPs-induced hot electron injection. The above results suggest that the present NIRPD will have great potential in future optoelectronic devices application.