The Electronic Properties of 30nm Meta-lattice Made by High Pressure CVD

A nanoscale 3D superlattice, called meta-lattice, can be synthesized by infiltrating a template of close-packed nanometer-scale silica spheres with Si or Ge by high pressure chemical vapor deposition. Their structures can be controlled by using different size spheres; accordingly, their electronic properties are geometry-dependent, hence they offer a platform to create systems with both quantum confinement and extended electronic states in three dimensions. We employ a tight binding method to calculate the electronic structure of a silicon meta-lattice containing more than 68,000 atoms in the unit cell formed from a 30-nm diameter sphere template. Our structural model is designed to minimize the surface free energy while respecting the template geometry. The Implicitly Restarting Arnoldi Method is implemented with a MPI code to solve the large Hamiltonian. The resulting electronic structure is compared to experimental spatially resolved EELS measurements showing location-dependent quantum confinement.