Tunable Optical Properties of Thin Films Controlled by the Interface Twist Angle

• DOI: 10.1021/acs.nanolett.0c04924
• Publication Date: 2021-02-17T02:19:08Z
• Authors: Hae Yeon Lee; Mohammed M. Al Ezzi; Nimisha Raghuvanshi; Jing Yang Chung; Kenji Watanabe; Takashi Taniguchi; Slaven Garaj; Shaffique Adam; Silvija Gradečak
• Keywords: Cathodoluminescence; Moiré pattern

Control of materials properties has been the driving force modern technologies. So far, have modulated by their composition, structure, and size. Here, using cathodoluminescence in a scanning transmission electron microscope, we show that optical stacked, >100 nm thick hexagonal boron nitride (hBN) films can be continuously tuned relative twist angles. Due to formation moiré superlattice between two interface layers twisted films, new sub-band gap is formed with decreasing magnitude as function angle, resulting tunable luminescence wavelength intensity increase >40×. Our results demonstrate phenomena extend beyond monolayer-based systems preserved technologically relevant, bulklike material at room temperature, dominating hBN for applications medicine, environmental, or information