First-Principle Investigation of zb-TiGe: A Promising Narrow Bandgap Semiconductor

Using first-principle calculations, a new compound semiconductor based on titanium (Ti) is predicted. It has been observed that Ti when alloyed with germanium (Ge) can crystallize in the zincblende symmetry, and exhibits semiconducting nature with a narrow bandgap. To test the robustness of the semiconducting nature, the structural properties and electronic band structure have been modeled using three different exchange-correlation functionals, namely, local density approximation, generalized gradient approximation, and Perdew-Burke-Ernzerhof for solids. With a nominal composition of 1:1, TiGe exhibits a direct bandgap of 0.58 eV at the "X" point of the Brillouin zone. From lattice dynamics, the structural stability of the compound has been established. The new semiconductor is characterized in detail for its electronic band structure, carrier effective mass, charge density distribution, and linear optical properties. Zb-TiGe exhibits large effective mass for conduction band holes and tentatively becomes a prototype system to study heavy holes resulting in carrier condensation at the bottom of the conduction band. The linear optical properties of the TiGe are found to be suitable for photosensitive devices in the infrared region. In addition, TiGe may find application in deep-UV and far-UV regions because of the surface plasmon resonance at 6.4 eV. Herein, TiGe is presented as a new narrow bandgap semiconductor with zincblende symmetry. Using first-principles calculation, it is predicted that TiGe in nominal composition of 1:1 can be a semiconductor with a bandgap of 0.58 eV. The stability of the lattice is supported by the studies of lattice dynamics.image (c) 2024 WILEY-VCH GmbH