PL SPECTRA AND QUANTUM CONFINEMENT ANALYSIS OF Ge NANOSTRUCTURE IN RAPID OXIDATION OF SiGe SUBSTRATE

Abstract

The investigation on the oxidation behavior of Si 1-x Ge x alloys (x=0.05, 0.15 and 0.25) is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8~2.8 nm and a few Ge nanoparticles with diameters ranging from 5.5 nm to 10 nm are formed by rapid oxidation of Si 1-x Ge x substrate. A new scanning method on the decline cross-section of the multiple layer sample is adapted to measure the layer thickness and the composition. Some new peaks in photoluminescence (PL) spectra are discovered, which could be related to the nano-cap and the nanoparticles of germanium. A suitable model and several new calculating formulas with the unrestricted Hartree–Fock–Roothaan (UHFR) method and quantum confinement analysis are proposed to interpret the PL spectra and the nano-structure mechanism in the oxide.