Abstract
We have fabricated GaP/InAs islands/GaP structures using various growth sequences for the GaP cap layer, by low-pressure organometallic vapor phase epitaxy (LP-OMVPE). The effects of the growth sequences on the buried InAs islands and the GaP cap layers have been investigated by cross-sectional transmission electron microscopy (TEM). The two-step growth sequence is effective for the growth of GaP cap layers, whereby the first GaP layer is grown at the same temperature as InAs islands and the second GaP layer is successively grown at the optimized growth temperature of GaP. The growth sequence yields good-quality GaP/InAs islands/GaP structures with small InAs islands (15 nm in width and 5 nm in height) and a high-quality GaP cap layer. Droplet heteroepitaxy of GaP cap layers is feasible for the control of the size of buried InAs islands.