Solution Processed Highly Responsive UV Photodetectors from Carbon Nanodot/Silicon Heterojunctions

Carbon nanostructures technology has recently emerged as a key enabler for next-generation optoelectronic devices working in the deep UV region due to their excitonic absorption. Here, we report the fabrication of “orange juice” derived solution processed carbon nanodots (CNDs)/n-Si heterojunction showing broadband spectral response with a peak responsivity of ∼1.25 A/W in UV (∼300 nm) wavelength. The surface topography and chemical information on synthesized CNDs via a facile synthesis route have been characterized showing the presence of surface chemical states resulting broad optical emission. The CNDs/n-Si photodiode exhibits very low dark current (∼500 pA), excellent rectification ratio (∼5 × 103), and very good photomodulation in UV region. Our device exhibits better responsivity in DUV than state-of-the-art GaN based photodetectors. Solution-processability of the devices with superior optical properties of CNDs thus pave the way for future high-performance, low-cost DUV photodetectors.