Formation and optical properties of GaSb quantum dots epitaxially grown on Si substrates using an ultrathin SiO_2 film technique

摘要

We developed a technique for forming epitaxial GaSb quantum dots on Si substrates using ultrathin SiO_2 films that contain epitaxial Ge nuclei. Unlike Volmer-Weber-type GaSb quantum dots on Si, the dot density was higher (10~9-10~(12) cm~(-2)) and the dot size was controlled in the range of approximately 10-100 nm. The nucleation of quantum dots was initiated by trapping Ga atoms on the Ge nuclei. Photoluminescence spectroscopy measurement at 5 K revealed the quantum-confinement effect in GaSb dots causing the photoluminescence peak to be continuously blueshifted from 0.76 eV by ～30 meV when the base length of the dots decreases from 100 to 17 nm.