A detailed study of the electronic and optical properties of germanium nanotubes

Abstract

We employed first-principles calculations to investigate the electronic and optical properties of germanene nanotubes (GeNTs). Significant multi-orbital hybridizations lead to metallic and semiconducting behaviors in small-sized armchair and zigzag GeNTs, respectively. The changes in band gaps and subband dispersions with increasing diameter have been thoroughly understood by analyzing spatial charge densities and projected density of states. The optical absorption spectra exhibit diameter-dependent anisotropy and suggest a dimensional transition beyond a critical diameter. This comprehensive study not only deepens our understanding of GeNTs but also reveals new possibilities for various nanotechnology applications.