Siao Ming-Deng, Tsai Meng-Yu, Gandhi Ashish Chhaganlal, Wu Yi-Chung, Fan Ta, Hao Li-Syuan, Li I-Ling, Chen Sun-Zen, Liu Chang-Hua, Lin Yen-Fu, Yeh Chao-Hui
Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan.
ACS Appl Mater Interfaces. 2025 Jan 29;17(4):6521-6529. doi: 10.1021/acsami.4c16883. Epub 2025 Jan 13.
Semiconducting transition metal dichalcogenides (TMDs) possess exceptional photoelectronic properties, rendering them excellent channel materials for phototransistors and holding great promise for future optoelectronics. However, the attainment of high-performance photodetection has been impeded by challenges pertaining to electrical contact. To surmount this obstacle, we introduce a phototransistor architecture, in which the WS channel is connected with an alternating WS-WSe strip superstructure, strategically positioned alongside the source and drain contact regions. Illumination triggers efficient separation of photoexcited electrons and holes due to the type-II staggered band alignment within the superstructure. Consequently, the contact regions exhibit degenerately doped n WS and p WSe strips under light illumination, resulting in minimal contact resistivity with the metal electrodes. The resultant WS phototransistor exhibits a remarkable responsivity of 2.4 × 10 mA/W and an impressive detectivity of 2.6 × 10 Jones. Furthermore, our time-resolved measurements reveal the absence of persistent photoconductance. This proposed phototransistor architecture provides a route for high-performance photodetection, effectively surpassing previous limitations associated with electrical contact.
半导体过渡金属二硫属化物（TMDs）具有卓越的光电子特性，使其成为光电晶体管的理想沟道材料，并在未来光电子领域极具潜力。然而，与电接触相关的挑战阻碍了高性能光探测的实现。为克服这一障碍，我们引入了一种光电晶体管架构，其中WS沟道与交替排列的WS-WSe带状超结构相连，该超结构位于源极和漏极接触区域旁边。由于超结构内的II型交错能带排列，光照引发光激发电子和空穴的有效分离。因此，在光照下，接触区域呈现简并掺杂的n型WS和p型WSe条带，从而使与金属电极的接触电阻最小化。由此产生的WS光电晶体管表现出2.4×10 mA/W的显著响应度和2.6×10琼斯的出色探测率。此外，我们的时间分辨测量表明不存在持续光电导现象。这种提出的光电晶体管架构为高性能光探测提供了一条途径，有效超越了先前与电接触相关的限制。
