Photoluminescence excitation of Saxena's deep donor in AlGaAs

The deep donor level, deduced by Saxena from temperature- and pressure-dependent Hall measurements, has been identified by photoluminescence (PL) of Si-doped Al x Ga 1-x As. Its PL signal can be enhanced by selective excitation to an excited state of this centre. For 0.20<x<0.55 the excited state has a constant separation of 106 meV from the L minimum of the conduction band. The ionization depth of the ground state (referred to the L minimum) varies from 225 to 175 meV in this composition range.