Quantum dots, Ge(Si)/Si(001), produced by gas-source molecular-beam epitaxy at 575C were investigated by using energy-filtering transmission electron microscopy and X-ray energy dispersive spectrometry. The results revealed non-uniform compositional distributions in the quantum dots; with the highest Ge content at the dot center. The average Ge content in the quantum dots was much higher than in the wetting layer. The quantum-dot/substrate interface was moved to the substrate side. A proposed growth mechanism for the quantum dots was based upon the composition distribution and interfacial structures.

Alloying, Elemental Enrichment, and Interdiffusion during the Growth of Ge(Si)/Si(001) Quantum Dots. X.Z.Liao, J.Zou, D.J.H.Cockayne, J.Wan, Z.M.Jiang, G.Jin, K.L.Wang: Physical Review B, 2002, 65[15], 153306 (4pp)