K. A. Messalea, B. J. Carey, A. Jannat, N. Syed, M. Mohiuddin, B. Y. Zhang, A. Zavabeti, T. Ahmed, N. Mahmood, E. Della Gaspera, K. Khoshmanesh, K. Kalantar-zadeh and T. Daeneke
Nanoscale, Accepted Manuscript (2018)
Atomically thin, semiconducting transition and post transition metal oxides are emerging as a promising category of materials for high-performance oxide optoelectronic applications. However, the wafer-scale synthesis of crystalline atomically thin samples has been a challenge, particularly for oxides that do not present layered crystal structures. Herein we use a facile, scalable method to synthesise ultrathin bismuth oxide nanosheets using a liquid metal facilitated synthesis approach. Monolayers of α-Bi2O3 featuring sub-nanometre thickness, high crystallinity and large lateral dimensions could be isolated from the liquid bismuth surface. The nanosheets were found to be n-type semiconductors with a direct band gap of ~3.5 eV and were suited for developing ultra violet (UV) photodetectors. The developed devices featured a high responsivity of ~400 AW-1 when illuminated with 365 nm UV light and fast response times of ~70 µs. The developed methods and obtained nanosheets can likely be developed further towards the synthesis of other bismuth based atomically thin chalcogenides that hold promise for electronic, optical and catalytic applications.