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

摘要

Electronic properties of "free" n-In0.49Ga0.51P 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 (Dss) in energy with relatively low densities, leading to no pronounced Fermi-level pinning effect on the surface. The minimum Dss 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.