Nanostructure fabrication process for optoelectronic applications

Abstract

Silicon nanostructures present a new class of material systems that possess electrical and optical properties different from bulk and conventional thin film structures.We present a fabrication process for devices based on silicon nanopillars. The pillars were obtained by means of selforganized gold-chromium and polystyrene sphere masks and reactive ion etching of silicon. The evolution of pillar shape during reactive ion etching (RIE) was observed by scanning electron microscopy (SEM) and explained by combined effect of backscattering and polymerization. On this base the optimal modes for the RIE were found. Mask properties that influence on pillar size distribution (30-100 nm) and density can be simply changed by means of metal layers thickness or polystyrene sphere diameter. The presented fabrication process allows the production of silicon nanopillars with different shapes and heights (up to 600 nm) on 4" wafer. Properties of silicon nanostructures were investigated by photoluminescence (PL) and cathodoluminescence (CL) techniques. Electroluminescent devices, based on silicon nanostructures, were made after planarization and top electrode formation. Stable strong electroluminescence in visible and near JR range was observed.