Beschreibung:
<jats:p>The correlation between the light-emission intensity from SiGe mixed crystals and Ge surface segregation during molecular beam epitaxy has been investigated. Atomic-hydrogen-assisted molecular beam epitaxy was used to vary the surface-segregation length of Ge. Results show that the photoluminescence (PL) intensity was very strong in the region where the surface-segregation length was less than 7 nm. However, when the surface-segregation length exceeded 7 nm, the PL intensity decreased sharply. A one-to-one correspondence between the PL intensity and the Ge segregation length was obtained. This is attributed to the dependence of the surface segregation on the degree of randomness in the SiGe alloy.</jats:p>