Center for Materials Engineering

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Browsing Center for Materials Engineering by Author "Derese, Abraham"

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    First-Principles Study Of Van Der Waals Heterostructures of MoSeTe/ZnO for Investigating Photocatalytic Water-Splitting and Photovoltaic Applications
    (Addis Ababa University, 2023-06) Derese, Abraham; Georgies, Alene (PhD)
    Two-dimensional (2D) heterostructures have allowed for the development of novel properties with interesting applications in photocatalytic water splitting and optoelectronic devices. Electronic properties of ZnO and Janus MoSeTe monolayers were investigated using density functional theory (DFT)-based first-principles calculations, and depending on the lattice mismatch, layered 2D MoSeTe/ZnO heterostructures were produced. In this study, the first-principles van der Waals corrected density functional theory calculations were also performed on ABI_Se, ABI_Te, and ABII_Te heterostructure.Out of eight basic stacking patterns of the ZnO/MoSeTe hetero-bilayer designed, the ABII-Te stacking mode was a more stable stacking type due to the small lattice mismatch and the binding energy. The result showed that the band alignment for ABI_Se, ABI_Te, and ABII_Te was done on the electrical band structure and band edge positions, and confirmed type two band alignment. In addition, the ABI_Se, ABI_Te, and ABII_Te configurations of ZnO/MoSeTe vdW heterostructures are indirect band gap semiconductors. The investigated 2D ZnO/MoSeTe heterostructures have an acceptable band gap for solar applications, according to a first-principles study. The power conversion efficiency of ZnO/MoSeTe heterostructure is computed, and the results exhibit ABI_Se, ABI_Te, and ABII_Te stacking orientations have high efficiency with values of 22.26%, 22.31%and22.17%, respectively. Therefore, our findings show the heterostructures have reasonable band gaps and high PCE, and exhibit type-II band alignment, which are suitable candidates for solar cell application. Furthermore, for full water splitting heterostructures cannot satisfy the band edge requirements; however, the heterostructures are a good photocatalyst for the hydrogen evolution reaction. The heterostructure's ability to split water more effectively can be improved by moving the band edges position using strain and doping.