Optical investigation of the grwoth mode of stacked Ge dots on Si(100)

摘要

Self-assembled semiconductor islands have been intensively investigated as a basis of future electronic and optical devices. The island is known to develop in the Stranski-Krastanow growth mode; where beyond a critical thickness, a nucleation of islands on the wetting layer becomes energetically favorable since the gain of strain energy due to the partial strain relaxation overcompensates the increased surface energy. This simple approach is regarded as an attractive and promising route to the fabrication of the small islands which might act as quantum dots. However, to establish a method to achieve sufficiently uniform island sizes with regular spatial distribution still remains a critical issue. As a possible way to obtain the size uniformity, the growth of multilayer arrays of coherently strained islands was proposed to be useful [1]. To give deep insight on the initial stage of the stacking process, we investigated the growth mode of double Ge layers on Si(100).