First-principles study of the band structure and optical spectra of germanium carbide under mechanical strain

By using first-principles calculations, the electronic and optical properties of GeC sheet under strain have been investigated. The results demonstrate that both biaxial compressive and tensile strain change the band gap of GeC sheet. The capability of direct to indirect band gap transition is observed by exerting the in-plane biaxial strain on GeC sheet. Also, by applying the tensile (compressive) strain, the optical spectra are globally shifted toward lower (higher) photon energies. The results demonstrate that the electronic structure and optical properties of GeC sheet can be tuned by strain engineering and the GeC sheet can be a promising material for the future nano-based electrical and optical devices.