Structural and photoluminescence studies of Er implated Be doped and undoped low-temperature grown GaAs

Abstract

Characteristic 1.54 μm Er3+ emission has been observed from Er-implanted and annealed, low-temperature grown GaAs Be doped and undoped samples. Er plateau implantations (480, 155, and 40 keV successive implants) were performed at 300 °C covering calculated Er concentrations from 1018 up to 1020 Er/cm3. Cross-sectional transmission electron microscopy studies reveal very little structural damage for these elevated temperature implants up to an Er total fluence of 1.36 1014 Er/cm². No Er emission was observed from any of the as-implanted samples but it was observed after postimplantation annealings at 650 and 750 °C temperatures. The Er emission was significantly more intense after 650 °C anneals, for Be doped samples, and after 750 °C anneals for undoped samples. It appears on top of a broad background luminescence associated with midgap states. The Er emission intensity was found to scale linearly with the total Er implantation fluence up to Er concentration of ~ 1019 Er/cm3. Er precipitation was observed after 750 °C annealing for 1019 Er/cm3 samples, but could be observed for 1020 Er/cm3 Er-doped samples even after a 650 °C anneal. These precipitates are most likely ErAs.