In this work, we study the electronic structure, the effective mass, and the optical properties of the MoSSe/InS van der Waals heterostructures (vdWHs) by first-principles calculations. The results indicate that the MoSSe/InS vdWH is an indirect band gap semiconductor and has type-Ⅱ band alignment in which the electrons and holes located at the InS and the MoSSe side, respectively. The band edge position, the band gap and the optical absorption of the MoSSe/InS vdWH can be tuned when biaxial strains are applied. In addition, compared with MoSSe and InS monolayers, the optical absorption of the MoSSe/InS vdWH is improved both in the visible and the ultraviolet regions. These findings indicate that the MoSSe/InS vdWHs have potential applications in optoelectronic devices.

Whisper gallery mode (WGM) resonances and the coupling of excitons and WGMs are measured from ZnO microrod cavity in the visible and ultraviolet spectral ranges. The coupling of excitons and WGMs leads to split modes which exhibit a clear spatial dependence due to the uneven field distribution of WGM on ZnO microrod surface. Polarization dependent behavior together with a blueshift of the upper polariton branch mode are observed owing to the transition polarization of different types of excitons in the ZnO microcavity. Numerical simulations are carried out using finite element method to support the experimental results. This work reveals the spatial and polarization dependent exciton–photon coupling in a ZnO microrod which implies promising applications in photonic polariton field ranging from ultraviolet lasers, high-sensitivity detectors to optoelectronic devices

van der Waals heterostructures (vdWHs) have been widely studied due to their particular properties. In this work, the electronic structure and the optical properties of MoSSe/InSe vdWH are studied by first-principles calculations, and the changes of strain modulation properties are also discussed. Theoretical research shows that the MoSSe/InSe vdWHs have an indirect band gap and the band alignments are type-I and type-II correspond to two different stacking patterns, respectively. Compared with MoSSe and InSe monolayer, the optical absorption of the MoSSe/InSe vdWH in the visible and ultraviolet region is improved. In addition, the band gap, the band alignment, and the optical absorption of the MoSSe/InSe vdWH can be effectively modulated by biaxial strain. This work provides possibilities for the application of the MoSSe/InSe vdWH in optical devices, electronic devices and photocatalysis. (C) 2021 Elsevier B.V. All rights reserved.

High order phenomena in the visible range and with polarization dependence in the ultraviolet (UV) region of the microphotoluminescence (micro-PL) spectrum in whispering-gallery mode (WGM) ZnO microrod cavity have been thoroughly studied at room temperature. WGM ZnO microrod cavity with good crystallinity is produced by the CVD growth method, and the ZnO microrod structures are characterized by structural and optical methods. Through the micro-PL spectrum measurement of the ZnO microrod, it is found that high-order resonance peaks appeared in the visible region. The different polarization conditions can be adjusted by rotating the angles of the polarizer, and it is proved that the micro-PL spectrum has strong polarization-dependent behavior in the UV region. Our results imply broad application potentials in the study of ZnO microrod-based photonic cavity devices.