Incorporation of optically active erbium into GaAs using the novel precursor tris(3,5-di-tert-butylpyrazolato)bis(4-tert-butylpyridine)erbium

We have investigated the use of an alternative erbium precursor, tris(3,5-di-tert-butyl- pyrazolato)bis(4-tert-butylpyridine)erbium, to dope erbium into GaAs. The incorporated erbium forms an optically active center identified as Er–2O. The GaAs:Er formed using this precursor exhibits sharper and more intense optical emission, attributed to the Er–2O center, than that previously found with cylcopentadienyl-based erbium sources. Codoping GaAs:Er with shallow donors results in a quenching of the erbium-related luminescence, while codoping with shallow acceptors results in no significant change in the spectrum. Mechanisms for the observed luminescence-quenching behavior are discussed. Deep level transient spectroscopy performed on silicon or selenium codoped GaAs:Er showed the presence of several electron traps in the upper half of the band gap. The origins of these electron traps are considered.