ESR study of [formula omitted] codoped with oxygen grown by organometallic vapor phase epitaxy

Abstract

X-band ESR measurements of GaAs : Er grown at 543°C by organometallic vapor phase epitaxy (OMVPE) with and without an additional O 2 flow (samples I and II, respectively) have been performed at 3.5 K . Sample I shows an isotropic ESR signal around g=6 together with several anisotropic ESR signals in the g-value region from 0.7 to 3, while sample II shows only an isotropic ESR signal around g=6, suggesting the formation of Er-2O centers in sample I. We also observed the temperature dependence of the anisotropic signals in sample I from 3.5 to 15 K . The integrated intensity showed a maximum at 7 K suggesting that these ESR signals are coming from the excited states very close to the ground state. The ESR signal also turned out to be very sensitive to the growth temperature of GaAs : Er . GaAs : Er grown at 628°C by OMVPE with an additional O 2 flow (sample III) showed no ESR signal at 3 K . These results will be discussed in connection with PL results of samples I–III.