Nanoscale ErP islands on InP(001) substrate grown by organometallic vapor-phase epitaxy

We have investigated nanoscale ErP islands formed on InP(001) during Er exp osure in organometallic vapor-phase epitaxial growth by means of atomic for ce microscopy and scanning tunneling microscopy. Different features of surf ace morphologies are observed depending on the growth temperature and the E rP coverage. The generation of misfit dislocation arrays along the [(1) ove r bar 10] direction leads to anisotropic strain relaxation that originates from the anisotropy of the atomic bonds at the interface. The residual stra in of partially relaxed islands is similar to 2% for growth at 530 degrees C, which corresponds to the minimum of total areal energy of the strained h im. Current imaging tunneling spectroscopy shows a high tunnel current at d islocations and ErP island edges suggesting the existence of high-density-s urface states near the Fermi level and the decrease in tunneling barrier he ight.