Strain relaxation in GaAs islands on GaP(001)

The relaxation of elastic strain energy in GaAs islands grown on GaP(001) substrate was evaluated by using the Keating method based on the idea that the strain is relaxed at the free edges of islands. The calculation reveals that the strain is relaxed more efficiently in narrower islands. This is consistent with the experimental results on GaAs/GaP grown by molecular beam epitaxy (MBE). An optimum size to minimize the energy was obtained when we took the surface energy into account.