High-responsivity van der Waals Schottky photodiodes based on maskless etched wafer-scale silicon nanoholes

In this study, a 6-inch high-quality silicon (Si) nanoholes (NHs) wafer was successfully prepared by inductively coupled plasma (ICP) dry maskless etching, subsequently utilized in the fabrication of novel Ti ₃ C ₂ T _x /Si NHs van der Waals (vdW) Schottky photodiodes. This device leverages the light-trapping effect of Si NHs to enhance light absorption, thereby increasing the responsivity of the device from visible to near-infrared (NIR) light. Notably, the responsivity and detectivity of the device for 980 nm reached 2 A/W and 5.17×10 ¹² Jones, respectively, at a bias voltage of −2 V, significantly surpassing the most existing Schottky diodes. Moreover, the proposed device has been applied to photoplethysmography (PPG) system for more accurate signal acquisition and heart rate (HR) monitoring.