Mesoscopic pointlike defects in semiconductors: Deep-level energies

Mesoscopic pointlike defects are a class of extended defects with surfaces of minimal curvature that span in size from the point-defect limit ~multivacancy, antisite, impurity complex, etc.! to macroscopic inclusions or voids within a semiconductor host. The structural, electronic, and optical properties of these defects evolve continuously from the quantum-mechanical limit to the classical limit. Mesoscopic defects share some features in common with quantum dots, such as Coulomb-charging energies, but unlike quantum dots their electronic properties are dominated by the covalent bond energies of the defect-semiconductor interface. The deep-level energies of spheroidal mesoscopic defects are calculated self-consistently in the unrestricted Hartree-Fock approximation using an extension of the many-electron model of Haldane and Anderson. The calculations in GaAs reveal a high-multiplicity Coulomb ladder of discrete charge states distributed across the semiconductor band gap and centered on the charge neutrality level. @S0163-1829~98!07836-9#