Tunable Linearity of High-Performance Vertical Dual-Gate vdW Phototransistors.

Layered 2D semiconductors have been widely exploited in photodetectors due to their excellent electronic and optoelectronic properties. To improve their performance, photogating, photoconductive, photovoltaic, photothermoelectric, and other effects have been used in phototransistors and photodiodes made with 2D semiconductors or hybrid structures. However, it is difficult to achieve the desired high responsivity and linear photoresponse simultaneously in a monopolar conduction channel or a p-n junction. Here, dual-channel conduction with ambipolar multilayer WSe2 is presented by employing the device concept of dual-gate phototransistor, where p-type and n-type channels are produced in the same semiconductor using opposite dual-gating. It is possible to tune the photoconductive gain using a vertical electric field, so that the gain is constant with respect to the light intensity-a linear photoresponse, with a high responsivity of ≈2.5 × 104 A W-1 . Additionally, the 1/f noise of the device is kept at a low level under the opposite dual-gating due to the reduction of current and carrier fluctuation, resulting in a high detectivity of ≈2 × 1013 Jones in the linear photoresponse regime. The linear photoresponse and high performance of the dual-gate WSe2 phototransistor offer the possibility of achieving high-resolution and quantitative light detection with layered 2D semiconductors.

Xu J ，Luo X ，Hu S ，Zhang X ，Mei D ，Liu F ，Han N ，Liu D ，Gan X ，Cheng Y ，Huang W ... -  《-》

Dual-gate organic phototransistor with high-gain and linear photoresponse.

Chow PCY ，Matsuhisa N ，Zalar P ，Koizumi M ，Yokota T ，Someya T ... -  《Nature Communications》

Rational Design of WSe(2) /WS(2) /WSe(2) Dual Junction Phototransistor Incorporating High Responsivity and Detectivity.

The excellent semiconducting properties and ultrathin morphological characteristics allow van der Waals (vdW) heterostructures based on 2D materials to be promising channel materials for the next-generation optoelectronic devices, especially in photodetectors. Although various 2D heterostructure-based photodetectors have been developed, the unavoidable trade-off between responsivity and detectivity remains a critical issue for these devices. Here, an ingenious phototransistor based on WSe2 /WS2 /WSe2 dual-vdW heterostructures is constructed, performing both high responsivity and detectivity. In the charge neutrality point (gate voltage of -15 V and bias voltage of 1 V), this device demonstrates a pronounced photosensitivity, accompanying with high detectivity of 1.9 × 1014  Jones, high responsivity of 35.4 A W-1 , and fast rise/fall time of 3.2/2.5 ms at 405 nm with power density of 60 µW cm-2 . Density functional theory calculations, energy band profiles, and optoelectronic characteristics jointly verify that the high performance is ascribed to the distinctive device design, which not only facilitates the separation of photogenerated carriers but also produces a strong photogating effect. As a feasible application, an automotive radar system is demonstrated, proving that the device has considerable potential for application in vehicle intelligent assisted driving.

Luo Z ，Yang M ，Wu D ，Huang Z ，Gao W ，Zhang M ，Zhou Y ，Zhao Y ，Zheng Z ，Li J ... -  《Small Methods》

2D SiP(2)/h-BN for a Gate-Controlled Phototransistor with Ultrahigh Sensitivity.

Wang Z ，Wei L ，Wang S ，Wu T ，Sun L ，Ma C ，Tao X ，Wang S ... -  《-》

Ultrasensitive, Ultrafast, and Gate-Tunable Two-Dimensional Photodetectors in Ternary Rhombohedral ZnIn(2)S(4) for Optical Neural Networks.

Zhen W ，Zhou X ，Weng S ，Zhu W ，Zhang C ... -  《-》