Instability of various configurations of in nano-crystals on GaAs (100) by droplet epitaxy

Remarkably we observe the instability of various configurations of In nano-crystals on GaAs (100). Various configurations of In nano-crystals are formed by a droplet epitaxy (DE) approach using molecular beam epitaxy (MBE). The configurations of In nano-crystals are round, squares and elongated rod shapes. When In crystals are exposed to air, a random pit begins to form. The pit formation was observed to be as deep as over 10 nm underneath the GaAs surface. Regardless of the shapes and configurations, In crystals desorb from the GaAs surface, which results in the development of strip patterns over 10 μm wide and hundreds of μm long.