In Situ Defect Engineering of Controllable Carrier Types in WSe 2 for Homomaterial Inverters and Self-Powered Photodetectors.

WSe 2 has a high mobility of electrons and holes, which is an ideal choice as active channels of electronics in extensive fields. However, carrier-type tunability of WSe 2 still has enormous challenges, which are essential to overcome for practical applications. In this work, the direct growth of n-doped few-layer WSe 2 is realized via in situ defect engineering. The n-doping of WSe 2 is attributed to Se vacancies induced by the H 2 flow purged in the cooling process. The electrical measurements based on field effect transistors demonstrate that the carrier type of WSe 2 synthesized is successfully transferred from the conventional p-type to the rarely reported n-type. The electron carrier concentration is efficiently modulated by the concentration of H 2 during the cooling process. Furthermore, homomaterial inverters and self-powered photodetectors are fabricated based on the doping-type-tunable WSe 2 . This work reveals a significant way to realize the controllable carrier type of two-dimensional (2D) materials, exhibiting great potential in future 2D electronics engineering.