Self-organized Ge_1−x Sn _x quantum dots formed on insulators and their room temperature photoluminescence

Abstract

In this study, we examined the self-organized formation of Ge1−xSnx quantum dots (QDs) on insulators based on a simple sputtering process and considered their luminescence properties. First, we systematically discussed the control factors in the self-organized formation of Ge1−xSnx QDs; the introduced Sn content and the deposition temperature should be related to the surface-migration of Sn atoms. Under sufficiently controlled conditions, we achieved the self-organized formation of Ge1−xSnx QDs surrounded by amorphous-like shells with a dot size of 9.3 nm, Sn content of 19 ± 10%, and dot density of 1.5 × 1011 cm−2 and they showed a 2.0-µm photoluminescence peak at room temperature. Furthermore, the formation of multilayered Ge1−xSnx QDs structures was demonstrated, and they exhibited excellent thermal stability up to 400 °C while maintaining a dot-like morphology without causing the agglomeration. Therefore, the self-organized formation of Ge1−xSnx QDs is useful for realizing light-emitting devices for optical interconnects.