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

• 来源期刊: 中国物理（英文版）
• 关键词: low-temperature oxidation laser-assisted nano-structure PL spectra
• 年，卷（期）: 2006,（2）
• 页码范围: 389-393
• 页数: 5页
• 语种: 英文

摘要

The 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 1.8ranging from 5.5 nm to 10 nm are formed by the low-temperature 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.