Programmable Interfacial Band Configuration in WS2/Bi2O2Se Heterojunctions

Programmable Interfacial Band Configuration in WS2/Bi2O2Se Heterojunctions

ACS Nano

10.1021/acsnano.4c02496

http://dx.doi.org/10.1021/acsnano.4c02496

Hanwen Zhang, Jianhui Fu, Alexandra Carvalho, Eng Tuan Poh, Jing-Yang Chung, Minjun Feng, Yinzhu Chen, Bo Wang, Qiuyu Shang, Hengxing Yang, Zheng Zhang, Sharon Xiaodai Lim, Weibo Gao, Silvija Gradečak, Cheng-Wei Qiu, Junpeng Lu, Chunnian He, Tze Chien Sum, Chorng Haur Sow

18 June 2024

Zhang, H., Fu, J., Carvalho, A., Poh, E. T., Chung, J.-Y., Feng, M., Chen, Y., Wang, B., Shang, Q., Yang, H., Zhang, Z., Lim, S. X., Gao, W., Gradečak, S., Qiu, C.-W., Lu, J., He, C., Sum, T. C., & Sow, C. H. (2024). Programmable Interfacial Band Configuration in WS2/Bi2O2Se Heterojunctions. ACS Nano, 18(26), 16832–16841. https://doi.org/10.1021/acsnano.4c02496

van der Waals heterojunctions based on transition-metal dichalcogenides (TMDs) offer advanced strategies for manipulating light-emitting and light-harvesting behaviors. A crucial factor determining the light−material interaction is in the band alignment at the heterojunction interface, particularly the distinctions between type-I and type-II alignments. However, altering the band alignment from one type to another without hanging the constituent materials is exceptionally difficult. Here, utilizing Bi2O2Se with a thickness-dependent band gap as a bottom layer, we present an innovative strategy for engineering interfacial band configurations in WS2/Bi2O2Se heterojunctions. In particular, we achieve tuning of the band alignment from type-I (Bi2O2Se straddling WS2) to type-II and finally to type-I (WS2 straddling Bi2O2Se) by increasing the thickness of the Bi2O2Se bottom layer from monolayer to multilayer. We verified this band architecture conversion using steady-state and transient spectroscopy as well as density functional theory calculations. Using this material combination, we further design a sophisticated band architecture incorporating both type-I (WS2 straddles Bi2O2Se, fluorescence quenched) and type-I (Bi2SeO5 straddles WS2, fluorescence-recovered) alignments in one sample through focused laser beam (FLB). By programming the FLB trajectory, we achieve a predesigned localized fluorescence micropattern on WS2 without changing its intrinsic atomic structure. This effective band architecture design strategy represents a significant leap forward in harnessing the potential of TMD heterojunctions for multifunctional photonic applications.

Publisher Copyright

This research / project is supported by the National University of Singapore - Research Centre of Excellence award to the Institute for Functional Intelligent Materials
Grant Reference no. : EDUNC-33-18-279-V12

This research / project is supported by the National Research Foundation, Prime Minister's Office - Competitive Research Program
Grant Reference no. : NRF-CRP26-2021-0063

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see doi.org/10.1021/acsnano.4c02496

https://oar.a-star.edu.sg/communities-collections/articles/20408

1936-086X
1936-0851

Institute of Materials Research and Engineering