Laser Tuning in Layered -BN Crystals.

Integrated optics shows great potential in the current optical communication systems, sensor technology, optical computers, and other fields. Tunable laser technology within a certain range is the key to achieving on-chip optical integration; to realize which, Raman scattering is a competitive method that can effectively transfer incident laser energy to optical phonons due to the photon-phonon interaction. Here, we take hexagonal boron nitride as the energy conversion medium, and based on the angle-resolved polarized Raman spectroscopy, it is found that when laser polarization vector ⊥ axis, the spectrum obtains maximal scattering across the cross section and a minimal depolarization ratio.

Raman Tensor of Layered SnS.

Recently, tin disulfide (SnS) has become a hot research focus in various fields due to its advantages of a high transistor switching ratio, an adjustable band gap in visible light range, excellent Li storage performance, sensitive gas recognition, and efficient photocatalytic capability. However, at present, studies of its basic structure mostly stay on the regulation related to the number of layers. To maximize the value of SnS in the application design, this paper analyzes the angle-resolved polarized Raman spectra of SnS crystals grown under high-temperature sealing systems.

Raman Tensor of van der Waals MoSe.

Molybdenum selenide (MoSe) is a van der Waals layered crystal with both the anisotropic light absorption and light scattering outside its surface. At present, the study of the Raman tensor of MoSe, which affects and even determines the inelastic light scattering's anisotropy, is not sufficient. In this research, with the aim of studying the out-of-plane anisotropy, we performed systematic angle-resolved polarized Raman (APR) spectroscopy and abstracted complete Raman tensors both experimentally and theoretically.

Raman tensor of layered MoS.

Raman tensors, one of the basic physical properties of ${{\rm MoS}_2}$MoS, are rarely reported. Here, angle-resolved polarized Raman scatterings on basal and cross planes of layered ${{\rm MoS}_2}$MoS were carried out using the geometry configuration of parallel polarization, and the Raman tensors of three optical vibration modes were systematically studied. As a polar vibration mode, the differential polarizability of the ${{\rm A}_{1{\rm g}}}$A mode corresponding to the Raman tensor along the $c$c direction is larger than that along the $a$a direction.

Hydrogen Impurities in ZnO: Shallow Donors in ZnO Semiconductors and Active Sites for Hydrogenation of Carbon Species.

ZnO, as a low-cost yet significant semiconductor, has been widely used in solar energy conversion and optoelectronic devices. In addition, Cu/ZnO-based catalysts can convert syngas (H, CO, and CO) into methanol. However, the main concern about the intrinsic connection between the physical and chemical properties and the structure of ZnO still remains.

Critical conditions for the formation of p-type ZnO with Li doping.

The stability of Li dopants in ZnO is studied first-principles calculations with electric dipole correction. The formation energies of substitutional Li (Li), interstitial Li (Li) and the Li + Li complex are calculated in large supercells and the results are extrapolated to the limit of an infinite-sized supercell. The stabilities of 2Li and the Li + Li complex are found to depend on the temperature and absolute oxygen partial pressure.