Approaching the Robust Linearity in Dual-Floating van der Waals Photodiode

Two-dimensional (2D) material photodetectors have gained great attention as potential elements for optoelectronic applications. However, the linearity of the photoresponse is often compromised by the carrier interaction, even in 2D photodiodes. In this study, a new device concept of dual-floating van der Waals heterostructures (vdWHs) photodiode is presented by employing ambipolar MoTe₂ and n-type MoS₂ 2D semiconductors. The presence of type II heterojunctions on both sides of channel layers effectively depletes carriers and restricts the photocarrier trapping within the channel layers. As a result, the device exhibits robust linear photoresponse under photovoltaic mode from the visible (405 nm) to near-infrared (1600 nm) band. With the built-in electric field of the vdWHs, a linear dynamic range of ≈100 dB, responsivity of ≈1.57 A W⁻¹, detectivity of ≈4.28 × 10¹¹ Jones, and response speed of ≈30 µs are achieved. The results showcase a promising device concept with excellent linearity toward fast and low-loss detection, high-resolution imaging, and logic optoelectronics.