Modulated electronic properties of borophene nanoribbons using copper and oxygen atoms

The electronic and optical properties of borophene nanoribbons, influenced by the adsorption of copper (Cu) and oxygen (O) atoms in various configurations, were studied using first-principles calculations. The findings indicated that the most stable configuration, with the minimum adsorption energy of −9.09 eV, was achieved with double-upper center adsorbed double O atoms. By varying the adsorption positions and the number of Cu and O atoms, borophene nanoribbons were successfully tuned to transform into direct and indirect band-gap semiconductors. In particular, borophene nanoribbons with single and double-upper center adsorbed Cu atoms exhibited direct band gaps of 0.083 eV and 0.185 eV, respectively. In contrast, the double-upper center adsorbed double O atoms configuration resulted in an indirect band gap of 0.039 eV. The results further demonstrated that the Fermi levels crossed into the valence band, displaying p-type degenerate semiconductor characteristics for configurations with single and double-upper center adsorbed Cu atoms as well as double-upper center adsorbed double O atoms.