Efficient Direct Band-Gap Transition in Germanium by Three-Dimensional Strain

Complementary to the development of highly three-dimensional (3D) integrated circuits in continuation Moore’s law, there has been a growing interest new 3D deformation strategies improve device performance. To continue this search for techniques, it is essential explore beforehand, using computational predictive methods, which strain tensor leads desired properties. In work, we study germanium (Ge) under an isotropic on basis first-principles methods. The transport and optical properties are studied by fully ab initio Boltzmann equation many-body Bethe–Salpeter (BSE) approach, respectively. Our findings show that direct band gap Ge could be realized with only 0.70% triaxial tensile (negative pressure) without challenges associated Sn doping. At same time, significant increase refractive index carrier mobility, particularly electrons, observed. These results demonstrate huge potential exploring space semiconductors, potentially many other materials, optimize their