Vapor–Liquid–Solid Growth of Morphology-Tailorable WS2 toward P‑Type Monolayer Field-Effect Transistors

• Published in: ACS applied materials & interfaces Vol. 14; no. 40; pp. 45716 - 45724
• Main Authors: Xie, Jinan, Meng, Guodong, Chen, Baiyi, Li, Zhe, Yin, Zongyou, Cheng, Yonghong
• Format: Journal Article
• Language: English
• Published: American Chemical Society 12.10.2022
• Subjects: Functional Nanostructured Materials (including low-D carbon); vapor−liquid−solid growth; p-type FETs; first-principles calculations; monolayer WS2; morphology tailoring
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c13812

Although substantial efforts have been made, controllable synthesis of p-type WS2 remains a challenge. In this work, we employ NaCl as a seeding promoter to realize vapor–liquid–solid (VLS) growth of p-type WS2. Morphological evolution, including a one-dimensional (1D) nanowire to two-dimensional (2D) planar domain and 2D shape transition of WS2 domains, can be well-controlled by the growth temperature and sulfur introduction time. A high growth temperature is required to enable planar growth of 2D WS2, and a sulfur-rich environment is found to facilitate the growth of high-quality WS2. Raman and photoluminescence (PL) mappings demonstrate uniform crystallinity and high quantum efficiency of VLS-grown WS2. Moreover, monolayer WS2-based field-effect transistors (FETs) are fabricated, showing p-type conducting behavior, which is different from previous reported n-type FETs from WS2 grown by other methods. First-principles calculations show that the p-type behavior originates from the substitution of Na at the W site, which will form an additional acceptor level above the valence band maximum (VBM). This facile VLS growth method opens the avenue to realize the p–n WS2 homojunctions and p/n-WS2-based heterojunctions for monolayer wearable electronic, photonic, optoelectronic, and biosensing devices and should also be a great benefit to the development of 2D complementary metal–oxide–semiconductor (CMOS) circuit applications.