Long-Lived Resonance States in n -doped AlGaAs

The electronic properties of localized resonance states in III-V compound semiconductors are analyzed. In general, resonance states recombine rapidly with the band states. However, a new class of resonance states is found to be long-lived if their coupling to the lattice is sufficiently large. The recombination of these states with band states is thermally activated which leads to extremely long lifetimes at low temperatures. Such states can explain recent experiments suggesting long-lived resonance states associated with persistent photoconductivity and "DX centers" in n-doped Al_1-xGaₓAs for $x<0.2$.