Beyza Sarikavak-Lisesivdin

In this computational study, a novel borophene polymorph, Ogee-Borophene, characterized by irregular decagon-shaped hollows was reported. The structure involves a deviation from hexagonal configurations found in all other known borophene polymorphs. The decagon-shaped hollow is highly related to the anisotropy of the structure, which results in three types of boron atoms with different electronic properties in the structure. In the study, the electronic structure and density of states of this novel structure were investigated with the help of density functional theory calculations. The electronic structure of Ogee-Borophene shows Dirac cone formations near the Fermi level. The discovery of a novel borophene polymorph, Ogee-Borophene, with irregular-shaped hollows represents a different point of view in the 2D materials field. The unique electronic properties of this material suggest that Ogee-Borophene has the potential to be used in a variety of applications, including transistors, and selective sensor applications without the need for additional doping.

This study focuses on the growth and physical properties of ZnO thin films on different substrates grown by mist-CVD enhanced with ozone (O₃) gas produced by corona discharge plasma using O₂. Here, O₃ is used to eliminate the defects related to oxygen in ZnO thin films. ZnO thin films are grown on amorphous soda-lime glass (SLG) and single crystals SiO₂/Si (100) and c-plane Al₂O₃ substrates at 350°C of low growth temperature. All ZnO thin films show dominant (0002) diffraction peaks from X-ray diffraction (XRD). As expected, full width at half maximum (FWHM) of (0002) is decreasing in ZnO thin films on single-crystal substrates, especially c-Al₂O₃ due to similar crystal structure. It is found that the strain in the films is lowest in ZnO/c-Al₂O₃. The surface morphologies of the thin films are studied with atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements. Grown ZnO films have a hexagonal and triangular nanostructure with different nanostructure sizes depending on the used substrate types. The calculated surface roughness is dramatically decreased in ZnO/c-Al₂O₃ compared to the other grown structures. The confocal Raman measurements show the E₂(H) peak of ZnO thin films at 437cm⁻¹. It is suggested that O₃ gas produced by corona discharge plasma using O₂ can be useful to obtain better crystal quality and physical properties in ZnO thin films.