Study on hot electron photoconversion in individual embedded gold/silicon nanohole

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The decay of surface plasmons in metal nanostructures followed by the generation of hot electrons has attracted widespread attention from researchers due to its potential for injecting into silicon to generate photocurrent and achieve infrared photodetection. However, the extremely low photoconversion efficiency of hot electrons limits their large-scale practical application. Despite extensive research on hot electron devices based on various gold/silicon nanoholes (Au/Si NHs), understanding of hot electron photoconversion in individual Au/Si NHs remains inadequate. In this study, we systematically investigated the hot electron response of individual Au/Si NHs. Many randomly distributed independent Au/Si NHs were fabricated using nanosphere lithography and metal-assisted chemical etching (MACE). By employing photocurrent mapping (PCM), the response of Au NHs to hot electrons was directly correlated. The results revealed that the photocurrent response at Au/Si NHs was significantly higher than that on planar Au films. The photocurrent increased continuously with the increasing depth of Au/Si NH embedding, and the circular spots corresponding to the positions of Au NHs in the PCM gradually enlarged, with the position of maximum photocurrent response shifting from the center to the edge of the holes. Additionally, we compared the photocurrent of multiple Au NHs on different samples and positions at different wavelengths, all showing good consistency and uniformity. Our study on the hot electron response of individual Au NH contributes to optimizing the structure of hot electron photodetectors and improving the photoconversion capability of metal/semiconductor devices.