Surface Fermi-level position and gap state distribution of InGaP surface grown by metalorganic vapor-phase epitaxy

摘要

Electronic properties of "free" n-In_(0.49)Ga_(0.51)P surfaces grown by metalorganic vapor-phase epitaxy were directly characterized using the contactless capacitance-voltage technique. The HCl-treated surface showed a wide and continuous distribution of surface state density (D_(ss)) in energy with relatively low densities, leading to no pronounced Fermi-level pinning effect on the surface. The minimum D_(ss) value was determined to be 8×10~(11) cm~(-2) eV~(-1). The surface Fermi-level position was found at 1.2 eV above the valence band maximum, consistent with the x-ray photoelectron spectroscopy results.