摘要
High endurance of noise fluctuation and environmental humidity of ultraviolet (UV) photodetectors has been considered a promising feature in practical assessments, yet rare reports have addressed this aspect. Herein, the facile solution-based synthesis of distributed carbon quantum dots (DCQDs) is explored, where the adjacent spacing of deposited CQD clusters can be readily adjusted by tailoring the deposition cycles of drop coating process and hydrophobic treatment on Si substrates. Results display the remarkably suppressed noise patterns of DCQD/Si-based photodetectors, whose two types of device detectivity, including dark currents (Ddark = 1.41 × 1012 Jones) and noise fluctuations (Dnoise = 4.66 × 1011 Jones) exhibit an order of improvement overwhelming those results of conventional CQD film/Si, respectively. These features are further interpreted by the experimental examinations of band structures and conduction mechanism of DCQD/Si heterostructures, illustrating the dual contributions of on-state current rectification and the emergence of short carrier-diffusion length at QD/Si contact. In addition, the DCQD/Si-based UV photodetectors display environmentally stable photodetection characteristics, with trivial degradation of sensing responsivity and detectivity of 3.6 % and 5.4 %, respectively, within the high environmental humidity of 50.2–90.3 %.
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