Self-assembled germanium nano-structures by laser-assisted oxidation

The investigation on the oxidation behaviour of Si自聚集锗 纳米结构 激光辅助氧化 PL光谱low-temperature oxidation, laser-assisted, nano-structure, PL spectraProject supported by the Natural Science Foundation of Guizhou Province, China (Grant No 3067(2004)).2005-04-202005-04-202005-10-08The investigation on the oxidation behaviour of Si1-xGex 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 1.8-2.8nm and a few Ge nanoparticles with diameters ranging from 5.5 nm to 10 nm are formed by the low-temperatu.re laser-assisted dry oxidation of Si1-xGex substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted 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 nano-particles of germanium. A suitable model and several new calculating formulae 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.

Self-assembled germanium nano-structures by laser-assisted oxidation

The investigation on the oxidation behaviour 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--2.8nm and a few Ge nanoparticles with diameters ranging from 5.5 nm to 10 nm are formed by the low-temperature laser-assisted dry oxidation of Si$_{1 - x}$Ge$_{x}$ substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted 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 nano-particles of germanium. A suitable model and several new calculating formulae 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.