Article ID Journal Published Year Pages File Type
10633657 Optical Materials 2005 4 Pages PDF
Abstract
The growth and photoluminescence of Ge(Si) self-assembled islands on strained Si1−xGex layers (0 < x < 20%) has been investigated. Both island size and density increase when the Ge content in the predeposited Si1−xGex alloy increases. The increased island density is associated with an enhanced surface roughness after SiGe deposition. The increased island size is attributed to enhanced Si intermixing and to a wetting layer thickness reduction. The latter is caused by accumulation of elastic strain energy in the SiGe layer. The increase in both island size and density leads to a strong interaction between neighboring islands. The island-island interaction results in island self-ordering, which is analyzed using a surface autocorrelation function. The lower Ge content in the islands accounts for the observed blueshift of the island related photoluminescence signal. We observe a room temperature photoluminescence signal for Ge islands grown on a predeposited SiGe alloy which is higher than for Ge islands grown on Si(0 0 1). This result is explained by an increased island density, which provides an efficient way to capture charge carriers in the islands.
Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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