Hybrid nano-scale Au with ITO structure for a high-performance near-infrared silicon-based photodetector with ultralow dark current

An internal photoemission-based silicon photodetector detects light below the silicon bandgap at room temperature and can exhibit spectrally broad behavior, making it potentially suited to meet the need for a near-infrared pure Si photodetector. In this work, the implementation of a thin Au insertion layer into an ITO/n-Si Schottky photodetector can profoundly affect the barrier height and significantly improve the device performance. By fabricating a nanoscale thin Au layer and an ITO electrode on a silicon substrate, we achieve a well-behaved ITO/Au/n-Si Schottky diode with a record dark current density of 3.7 × 10-7 A/cm2 at -1 V and a high rectification ratio of 1.5 × 108 at ±1 V. Furthermore, the responsivity has been obviously improved without sacrificing the dark current performance of the device by decreasing the Au thickness. Such a silicon-based photodetector with an enhanced performance could be a promising strategy for the realization of a monolithic integrated pure silicon photodetector in optical communication.