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.