Direct energy gap of Al1−<i>x</i>In<i>x</i>As lattice matched to InP

Abstract

The direct energy gap of thin, undoped epitaxial layers of Al1−xInxAs grown on (100) InP has been measured as a function of In content for values of x between 0.46 and 0.55 using catholuminescence spectroscopy. For the composition lattice matched to InP it was measured to be 1.450 eV at room temperature, and 1.508 eV at 4 K. Over the limited range of compositions studied, it varied as Eg =1.450+2.29 Δx eV at room temperature, and as Eg =1.508+2.22 Δx eV at 4 K, where Δx=(0.52−x), the deviation of x from the lattice-matched value.