Thermally activated de‐excitation of the EL2 metastable state in GaAs

Measurements of absorption in the near infrared have been performed on n-type and undoped semi-insulating GaAs containing EL2 the main native defect in GaAs. The whole band of absorption related to EL2 disappeared after 1 μm light illumination when the crystal was cooled to helium temperatures. Measurements of the thermally activated recovery of EL2 absorption have been made. The rate of the de-excitation is well described by the formula: r = 1.7 · 1012 · exp (−0.36 eV/kT) + 1.6 · 10−9 · n · exp (−0.085 eV/kT) s−1 where n [cm−3] is the concentration of free electrons.