Highly sensitive active pixel image sensor array driven by large-area bilayer MoS2 transistor circuitry

Various large-area growth methods for two-dimensional transition metal dichalcogenides have been developed recently for future electronic and photonic applications. However, they have not yet been employed for synthesizing active pixel image sensors. Here, we report on an active pixel image sensor array with a bilayer MoS2 film prepared via a two-step large-area growth method. The active pixel of image sensor is composed of 2D MoS2 switching transistors and 2D MoS2 phototransistors. The maximum photoresponsivity (R-ph) of the bilayer MoS2 phototransistors in an 8 x 8 active pixel image sensor array is statistically measured as high as 119.16AW(-1). With the aid of computational modeling, we find that the main mechanism for the high R-ph of the bilayer MoS2 phototransistor is a photo-gating effect by the holes trapped at subgap states. The image-sensing characteristics of the bilayer MoS2 active pixel image sensor array are successfully investigated using light stencil projection. Here, the authors report the realization of an active pixel image sensor array composed by 64 pairs of switching transistors and phototransistors, based on wafer-scale bilayer MoS2. The device exhibits sensitive photoresponse under RGB light illumination, showing the potential of 2D MoS2 for image sensing applications.

Automated summary

Various large-area growth methods have been developed for two-dimensional transition metal dichalcogenides, but have not been used for synthesizing active pixel image sensors. An active pixel image sensor array with bilayer MoS2 film was successfully prepared and exhibited high photoresponsivity. The main mechanism for the high photoresponsivity of bilayer MoS2 phototransistors is attributed to a photo-gating effect by holes trapped at subgap states.