Formation and Opto-electronic Properties of Nanostructures on Ultrathin SiO2-Covered Si Surfaces

Abstract

We review a method to form semiconductor nanodots on Si substrates by using ultrathin Si oxide technology and the results on their opto-electronic properties. We can form ultrasmall semiconductor nanodots with the size of ∼5 nm and ultrahigh density of ∼1012 cm−2 on Si surfaces covered with ultrathin SiO2 films of ∼0.3 nm thickness. We focus on the Ge, GeSn, and GaSb nanodots on Si substrates and those embedded in Si films. These structures exhibit quantum confinement effects and intense luminescence in the energy region of about 0.8 eV. We also report an application result to grow GaSb thin films on Si substrates covered with ultrathin SiO2 films using GaSb nanodots as seeding crystals.