Enhancement of near ultraviolet spectral range responsibility of silicon photodetectors via additional fluorescent InP/ZnS quantum dots layer

Abstract

Silicon (Si) photodetectors are utilized in numerous fields ranging from various optical interconnects via spectroscopy application to industrial process control. Despite this, the generally adopted Si photodetectors tends to be more sensitive to red and near-infrated light than blue and near ultraviolet (NUV) light. Here, a new type of hybrid photodetector made by integrating solution-processed ultrathin fluorescent InP/ZnS quantum dots (QDs) layer onto a Si photodetector is conceived and demonstracted. The optimized hybrid photodetector achieves favorably enhanced near ultraviolet (NUV) spectral range responsibility between 300 nm and 450 nm without introducing any deteriorated photodetection performance of the Si photodetector beyond short-visible wavelength band. The photoresponsivity of the optimal hybrid device reaches 0.022 A/W at the wavelength of 380 nm and increased by a factor of 6.1 relative to a commercial Si based photodetector without additional InP/ZnS QDs ultrathin layer, while simultaneously achieving high on/off ratio under 0 V working voltage. The proposed approach and findings represent a promising strategy in the quest for low-cost and broadband photodetectors with compact architecture that is directly compatible with nowadays integrated circuit technology.