Self-assembled Ge islands were grown on Si(100) substrate by Si2H6-Ge molec
ular beam epitaxy. After being subjected to chemical etching, it is found t
hat the photoluminescence from the etched Ge islands became more intense an
d shifted to the higher-energy side compared to that of the as-deposited Ge
islands. This behaviour was explained by the effect of chemical etching on
the morphology of the Ge islands. Our results demonstrate that chemical et
ching can be a way to change the luminescence property of the as-deposited
islands.