Deep center inAl0.3Ga0.7As

We report the observation of a new trapping center in ${\mathrm{Al}}_{0.3}$ ${\mathrm{Ga}}_{0.7}$As. The center becomes active under a hydrostatic pressure of ∼45 kbar, and has an unusually deep emission barrier. It quenches all radiative transitions and causes a hysteresis in the photoluminescence intensity, which we interpret via a lattice-relaxation model. It is neither the DX nor the SD center, and probably related to a donor.