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

Abstract

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 8ϫ10 11 cm Ϫ2 eV Ϫ1 . The surface Fermi-level position was found at 1.2 eV above the valence band maximum, consistent with the x-ray photoelectron spectroscopy results.

Surface potential in n- and p-GaInP2(100): temperature effect

“…For n-GaInP 2 (100) with the doping density of p ∼ 10 17 cm -3 the band bending can be calculated as 350 and 140 meV at 300 and 77 K, respectively (δ = 2.5). Solving the equation ( 8), one can obtain that the level of the surface states occurs at the energy of 0.74 eV below the conduction band minimum, the broadening of the surface states level is about 130 meV, and the surface states density is of about 2 × 10 12 cm -2 (figure 5(a)), which is in a good agreement with the data obtained previously for the HCl-etched n-GaInP 2 (100) surface [16]. For p-GaInP 2 (100) (band bending is 370 and 130 meV at 300 and 77 K, respectively δ = 2.8) similar calculations give the energy of the surface states of 0.64 eV above the valence band maximum, the broadening of the surface state level is 240 meV, while the surface states density is of the order of 7 × 10 12 cm -2 (figure 5(b)).…”

“…In addition, GaInP can be used as passivating layer in GaAs bipolar transistors [13], or nanowire photocathodes for water splitting [14]. These applications promote investigations of the GaInP surface electronic structure [15,16]. Moreover, * Author to whom any correspondence should be addressed.…”

“…The electronic structure of the n-GaInP 2 (100) surface was studied by the contactless capacitance-voltage technique (C-V) and x-ray photoemission spectroscopy (XPS) [16]. It was found that a low density of states characterizes this surface without pronounced pinning of the Fermi level.…”

The influence of the InGaP window layer on the optical and electrical performance of GaAs solar cells

“…It is known that the degree of order, and hence the band gap, observed in the lattice of materials containing III group elements is influenced by the growth conditions [30]. Values ranging from 1.80 eV for an ordered lattice to 1.9-2.0 eV for a disordered one [31][32][33][34] have been reported for InGaP. Based on these data, we can consider the material used for these simulations as partially ordered.…”

AlGaAs/InGaP interfaces in structures prepared by MOVPE

“…In 0.485 Ga 0.515 P (hereafter InGaP) is chemically more stable than AlGaAs. It has a lower density of surface states [4], and it exhibits a good etching selectivity with respect to GaAs. However, unlike AlGaAs, In x Ga 1Àx P is lattice matched to GaAs only at the In 0.485 Ga 0.515 P composition.…”