Epitaxial growth of ultrahigh density Ge1−xSnx quantum dots on Si (111) substrates by codeposition of Ge and Sn on ultrathin SiO2 films

Abstract

A method to form epitaxial Ge1−xSnx quantum dots (QDs) on Si (111) substrates has been developed by codeposition of Ge and Sn on ultrathin SiO2 films with predeposited Ge nuclei. Hemispherical Ge1−xSnx QDs with an ultrahigh density (∼1012 cm−2) were epitaxially grown in the nanometer-size range. The QD size was controlled by changing the GeSn deposition amount. High-resolution transmission electron microscopy observations revealed that the main formed Ge1−xSnx QDs had less strain and no misfit dislocations.