Acceptorlike ExcitedSStates of Excitons Bound to Nitrogen Pairs in GaP

Abstract

The photoluminescence excitation spectra of excitons in GaP, bound to isoelectronic electron traps by more than 40 meV, show series of levels whose energies agree well with effective-mass calculations of the $\mathrm{nS}$ levels of an acceptor, which are inaccessible by other techniques. This is the first detailed investigation of the internal structure of excitons bound to isoelectronic traps. It confirms the Hopfield-Thomas-Lynch model and establishes its range of validity.