Visible–near‐infrared wavelength‐selective photodetection and imaging based on floating‐gate phototransistors

Abstract Wavelength selective imaging has a wide range of applications in image recognition and other application scenarios, which can effectively improve the recognition rate of objects. However, in the existing technical scenarios, it is usually necessary to use complex optical devices such as filters or gratings to achieve wavelength extraction. These methods inevitably bring about the problems of complex structure and low integration. Therefore, it is necessary to realize the wavelength extraction function at the device level. Here, we realize the wavelength extraction function and wide‐spectrum imaging function in the visible to infrared band based on a visible light absorber/floating gate storage layer/near‐infrared (NIR) photogating layer configuration. Under infrared irradiation, the device exhibits negative photoresponse through the absorption of infrared light by the Ge substrate and the photogating effect, and realizes visible positive light response through the absorption of visible light by MoS 2 . Utilizing the memory function of the device, by cleverly changing the gate voltage pulse, the photoresponse state of the output voltage is effectively adjusted to achieve three imaging states: visible light response only, response to both visible and infrared light, and infrared light response only. Active selective imaging of the word “XDU” was achieved at 532 and 1550 nm wavelength. By using the photoresponse data of the device, the passive imaging of the topography of Xi'an, Shaanxi Province was obtained, which effectively improves the recognition rate of mountains and rivers. The proposed reconfigurable visible–infrared wavelength‐selective imaging photodetector can effectively extract image information and improve the image recognition rate while ensuring a simple structure. The single‐chip‐based spectral separation imaging solution lays a good foundation for the further development of visible–infrared vision applications. image