High‐performance silicon‐based PbSe-CQDs infrared photodetector

Abstract

Silicon technology is dominant in electronics and optoelectronics. The cut-off wavelength of silicon is less than 1.1 $$\upmu$$ m due to the bandgap, limiting applications of silicon in communication, sensing, and light harvesting. A new strategy for infrared photodetection is presented by integrating silicon and PbSe colloidal quantum dots (CQDs), which combines advantages of silicon devices and PbSe-CQDs. In this study, we introduce a silicon-based photodetector that is sensitive to infrared light with spectral response from 405 nm to 1550 nm. The device can deliver a high responsivity of 648.7AW− 1 and a fast response of 32.3 $$\upmu$$ s at 1550 nm. Besides, the detectivity and the external quantum efficiency of the device reached 7.48 × 1010 Jones and 6.47 × 104%, respectively. The performance of the device originates from the photovoltage generated at the interface between the silicon and the quantum dots. This photovoltage changed the width of the depletion layer to realize detection. These results indicate that the silicon-based quantum dot infrared photodetectors prepared by this method have application prospects in the field of optoelectronics.