In situ STM observation during InAs growth in nano holes at 300 °C

We have successfully confirmed that In atoms were favored to congregate inside hole structures, during In and As₄ irradiations, by a STMBE system which was a scanning tunneling microscope located inside a molecular beam epitaxy growth chamber. After forming 1.5 monolayer of InAs wetting layer (WL) on a GaAs(001) surface, we applied voltage at a particular site on the WL during As₄ irradiation at 300 °C, creating hole structures (widths: 33–66.1 nm, depths: 4.9–9.7 nm). With the In and As₄ irradiations, spontaneously, In atoms on the WL were congregated inside the holes, decreasing the volume of the hole structures. It was found that InAs growth rates inside the hole structures were 23.1–217 times larger than that at the WL growth region near the holes.