Molecular-beam epitaxy of InAs on GaAs substrates with hole arrays patterned by focused ion beam

Abstract

InAs was grown by molecular-beam epitaxy on (0 0 1) GaAs substrates with triangular arrays of holes, which were patterned by focused ion beam. In the case of the growth on large and deep holes (diameter: 400–500 nm, depth: 50–300 nm, pitch: 600 nm), InAs was grown laterally on the sidewall of the hole, and the other dots were not grown around the holes. The lateral film thickness of InAs increased as the depth of holes was decreased, and a large InAs dot with an average diameter of 400 nm was grown on a hole with a depth of 50 nm. On the other hand, in the case of the growth on hole arrays with small (0 0 1) regions (hole diameter: 300 nm, depth: 300 nm, pitch: 400 nm), lateral growth on the sidewall of the hole was not observed, but many Stranski–Krastanov dots were grown at the bottom of holes. These results indicated that the amount of In supplied from (0 0 1) regions between the holes to sidewalls affected InAs nucleation sites around the holes and the growth mode.