We fabricated InAs nanoscale rings on InP substrates by droplet epitaxy. The rings were formed on an InGaAs layer with a thickness of d (d=0, 3, 4, and 10 nm), below which a 10-nm-thick InAlAs layer was deposited. While the ring was closed when d=10 nm, it was of C-shape when d=3 and 4 nm. Furthermore, in the former ring, a 10-nm deep hole was formed at its center and, in the latter ring, the depth of the hole was only 3 to 4 nm. The change in the ring shape is discussed in terms of behaviors of In droplets during crystallization. Photoluminescence (PL) originating from the nanoscale rings was observed. (c) 2012 Elsevier B.V. All rights reserved.