High performance of a broadband room-temperature Si detector beyond the cut-off wavelength

Abstract

There is an urgent requirement to develop room temperature high performance broadband detectors to meet the growing demands in areas such as remote sensing and space observation. Silicon, as the most important material in semiconductors, has dominated the market for photodetectors. However, due to its band gap limitation, it is difficult for Si detectors to detect wavelengths above 1100 nm with high sensitivity at room temperature. Herein, we show that a Si detector is highly sensitive to both near infrared (NIR 1550 nm) and terahertz light using a 3D MSM structure based on multiple detection mechanisms. It achieves current responsivity of 0.69 A W⁻¹ at 1550 nm and high sensitivity detection of 0.058 pW Hz^−1/2 at 0.269 THz (1115 μm), as well as a fast response of 917 ns at room temperature. Room-temperature terahertz imaging is also performed to verify the excellent performance of the Si photoconductive detector. Our findings open a new avenue to achieve high-performance broadband photodetectors based on multiple detection mechanisms in NIR and terahertz light at room temperature beyond the cut-off wavelength of Si detectors.