Defect Induced Modifications in Optical Emission from Er³⁺ in Er₂O₃

Rare earth ions, such as Er³⁺, in solid state systems are critical to telecommunication applications. Since the emission properties depend on the crystal field, damage to the crystalline structure from ion irradiation may alter the photophysical properties of the Er³⁺, underscoring the need for an exploration on the influence of defects. Here we report measurements of temperature dependent photoluminescence (TDPL) from Er³⁺ in Er₂O₃ as a function of He+ ion irradiation. A sample consisting of 90 nm Er₂O₃ thin film epitaxially grown (MBE) on a Si (111) was studied. 30keV He+ ion beam irradiation was applied with fluences of 2*10¹⁴ atoms/cm² and 2*10¹⁵ atoms/cm², corresponding to 1% and 10% defect concentration according to SRIM. We study the TDPL for both visible and infare range. After ion irradiation, a significant enhancement of Er³⁺ emission from the ⁴F_9/2 excited state to ⁴I_15/2 ground state transition (λ = 658 nm) was observed, while another transition in the irradiated sample, ⁴S_3/2 excited state to ⁴I_15/2 ground state (λ = 546 nm) was not significantly affected. These findings demonstrate that ion irradiation can modify the photophysical properties of Er³⁺ in Er₂O₃, opening new avenues for the manipulation and modification of optical behavior, potentially enabling novel applications in quantum information science.