Surface Functionalization of Black Phosphorus via Potassium toward High-Performance Complementary Devices

4 years ago

Surface Functionalization of Black Phosphorus via Potassium toward High-Performance Complementary Devices

Li Wang, Jing Wu, Zehua Hu, Sherman J. R. Tan, Bo Lei, Wei Chen, Wei Huang, Fengwei Huo, Dianyu Qi, Yang Bao, Cheng Han, Kian Ping Loh, Du Xiang, Alexandra Carvalho, Lidia C. Gomes

Two-dimensional black phosphorus configured field-effect transistor devices generally show a hole-dominated ambipolar transport characteristic, thereby limiting its applications in complementary electronics. Herein, we demonstrate an effective surface functionalization scheme on few-layer black phosphorus, through in situ surface modification with potassium, with a view toward high performance complementary device applications. Potassium induces a giant electron doping effect on black phosphorus along with a clear bandgap reduction, which is further corroborated by in situ photoelectron spectroscopy characterizations. The electron mobility of black phosphorus is significantly enhanced to 262 (377) cm² V^–1 s^–1 by over 1 order of magnitude after potassium modification for two-terminal (four-terminal) measurements. Using lithography technique, a spatially controlled potassium doping technique is developed to establish high-performance complementary devices on a single black phosphorus nanosheet, for example, the p–n homojunction-based diode achieves a near-unity ideality factor of 1.007 with an on/off ratio of ∼10⁴. Our findings coupled with the tunable nature of in situ modification scheme enable black phosphorus as a promising candidate for further complementary electronics.

Publisher URL: http://dx.doi.org/10.1021/acs.nanolett.7b00903

DOI: 10.1021/acs.nanolett.7b00903