Jg. Cederberg et al., Incorporation of optically active erbium into GaAs using the novel precursor tris(3,5-di-tert-butylpyrazolato)bis(4-tert-butylpyridine)erbium, J APPL PHYS, 85(3), 1999, pp. 1825-1831
We have investigated the use of an alternative erbium precursor, tris(3,5-d
i-tert- butyl-pyrazolato)bis(4- tert-butylpyridine)erbium, to dope erbium i
nto GaAs. The incorporated erbium forms an optically active center identifi
ed 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 pr
eviously found with cylcopentadienyl-based erbium sources. Codoping GaAs: E
r with shallow donors results in a quenching of the erbium-related luminesc
ence, while codoping with shallow acceptors results in no significant chang
e in the spectrum. Mechanisms for the observed luminescence-quenching behav
ior are discussed. Deep level transient spectroscopy performed on silicon o
r selenium codoped GaAs: Er showed the presence of several electron traps i
n the upper half of the band gap. The origins of these electron traps are c
onsidered. (C) 1999 American Institute of Physics. [S0021-8979(99)10903-4].