Tensile-Strained Self-Assembly of InGaAs on InAs(111)A

We have determined a reproducible set of growth conditions for the self-assembly of tensile-strained In1-xGaxAs quantum dot (QD) nanostructures on (111)A surfaces. During molecular beam epitaxy, In1-xGaxAs islands form spontaneously on InAs(111)A when the Ga content x ≥ 50%. We analyze the structure and composition of InGaAs/InAs(111) samples using atomic force microscopy, transmission electron microscopy, and electron energy loss spectroscopy. We demonstrate control over the size and areal density of the islands as a function of In1-xGaxAs coverage, In1-xGaxAs composition, and substrate temperature. We calculated the conduction and valence band energy values for these QDs in an InAs matrix. This work supports the efforts to establish InAs(111)A as a platform for future incorporation with other (111)-oriented materials from the 6.1 Å family of semiconductors