Black Silicon Photodiodes for VUV Detection

Black silicon (b-Si) is an emerging material made by modifying silicon with nanostructures for improved photon detection. Photodetectors with b-Si has significantly increased the sensitivity from NIR to the visible wavelengths. Here, we measured the spectral responsivity of b-Si light-trapping photodiodes under Vacuum Ultraviolet (VUV) radiation at normal-incidence at ambient and in cryogenic temperature. The device exhibits an external quantum efficiency >100% below 200 nm with a responsivity of 0.2 A/W at 175 nm at room temperature. These results demonstrate new opportunities of this technology when applied to devices used for direct VUV photon detection in various scientific applications, including noble gas and liquid scintillating detectors, and could lead to the development of b-SiPM.