Tin dioxide quantum dots coupled with graphene for high-performance bulk-silicon Schottky photodetector

Abstract

Commercial photodetectors have been dominated by bulk silicon (B-Si) due to the maturity of Si technology. However, its relatively poor mobility has impeded B-Si from high-performance applications. Herein, we demonstrate that tin dioxide quantum dots (SnO₂-QDs) coupled with graphene produce a Schottky junction with B-Si to drastically promote the performance of the SnO₂-QDs/graphene/B-Si Schottky photodetector. This hybrid device is sensitive to broadband illumination covering the UV-vis-NIR region and shows high responsivity of 967.6 A W⁻¹ (nearly 4 orders higher than that of commercial B-Si Schottky photodetectors), with corresponding external quantum efficiency of 2.3 × 10⁵% and detectivity of 1.8 × 10¹³ Jones. In addition, the hybrid device manifests fast rise and decay times of 0.1 and 0.23 ms, respectively. These figures-of-merit are among the best values of the recently reported B-Si Schottky photodetectors. We also established that the superior performances are attributed to the strong light absorption of the hybrid structure and increased built-in potential of the graphene/B-Si Schottky junction, which allows efficient separation of photoexcited electron–hole pairs. These findings pave the way toward the rational design of optoelectronic devices through the synergetic effects of 2D materials with 0D and 3D semiconductors.