Deep-level traps and the conduction-band structure of InP

Abstract

Three traps found in n-type InP with emission activation energies ΔEe=0.43, 0.59, and 0.63 eV are analyzed. The position of the energy levels for these traps, relative to the lowest conduction-band minimum Γ, are ET=0.34, 0.20, and 0.24 eV, respectively. It is shown that the 0.43-eV trap emits to and captures electrons from the Γ minimum and exhibits a thermally activated capture cross section with a barrier energy of 0.09 eV. Very good agreement is found between the capture cross sections derived from capture and from emission experiments: σ∞=3.4×10−15 and 5.8×10−15 cm2, respectively. It is concluded from detailed emission and capture studies that the 0.59- and 0.63-eV traps emit and capture carriers via the higher-lying L minima. A value of 0.39 eV for the intervalley L-Γ energy separation is consistent with the observed emission and capture properties of both centers.