Energy level of the Si-related DX-center in (AlyGa1−y)1−xInxAs

Abstract

For the quaternary material (AlyGa1−y)1−xInxAs, the energy level of the silicon-related deep electron trap known as the DX-center is calculated. In addition, the composition range y(x) is derived, for which the silicon-related DX-center level is below the conduction band minimum and thus electronically active. Eventually, the result of the calculation is compared with available measurement data, revealing good agreement regarding the composition when the DX-center energy level crosses the conduction band minimum.

Middle Cell Development for Wafer-Bonded III-V//Si Tandem Solar Cells

“…As the diffusion length is smaller for the n-Ga 0.51 In 0.49 P barrier despite of the higher barrier and despite of the occurrence of nonradiative recombination centres, so called DX-centres, in n-Al 0.3 Ga 0.7 As:Si [31] this is an indication of a nonideal interface created during epitaxial growth at the arsenide-tophosphide change. Although increasing the aluminium content of the barrier beyond 0.4 reduces the detrimental effect of the DX-centres because of its energetic position inside the band gap [32] we observed an even lower diffusion length for an n-Al 0.8 Ga 0.2 As:Si barrier. This could mean that the reduced lifetime in Al 0.8 Ga 0.2 As due to high oxygen impurity densities overrides the benefit of the higher barrier and thus decreased penetration of the wave function.…”