Graphene on Self‐Assembled InGaN Quantum Dots Enabling Ultrahighly Sensitive Photodetectors

Abstract

Abstract Highly sensitive photodetection is indispensable in applications, such as remote sensing, imaging, and smoke alarming. III–V nitrides are promising candidates for photodetectors due to their continuously tunable bandgap, radiation hardness, and temperature stability. However, the sensitivity of traditional III–V nitride‐based photodetectors is limited by poor crystal quality which stems from lattice mismatch‐induced point defects and dislocations. Recently, a new type of graphene–colloidal quantum dot (QD) hybrid phototransistor has been preferentially used to obtain high detection sensitivity, but III–V nitride‐based colloidal QDs are hard to synthesize. Here, a highly sensitive QD/graphene hybrid photodetector is demonstrated by using self‐assembled InGaN QDs. The photoconductance in the 2D graphene sheet is tuned by photogenerated carriers in the quantum dots when illuminated, and this effect leads to a current gain mechanism. The photodetector achieves an ultrahigh responsivity over 10 9 A W −1 , a current gain of 10 9 and fW light detectivity even at room temperature. This study paves the way for new types of highly sensitive III–V nitride‐based photodetectors despite the insufficient crystal quality.