Enhancement of 1.53 μm photoluminescence from spin-coated Er–Si–O (Er2SiO5) crystalline films by nitrogen plasma treatment

Er–Si–O (Er2SiO5) crystalline films are fabricated by the spin-coating and subsequent annealing process. The fraction of erbium is estimated to be 21.5 at% based on Rutherford backscattering measurement. X-ray diffraction pattern indicates that the Er–Si–O films are similar to Er2SiO5 compound in the crystal structure. The fine structure of room-temperature photoluminescence of Er3+-related transitions suggests that Er has a local environment similar to the Er–O6 octahedron. Our preliminary results show that the intensity of 1.53 μm emission is enhanced by a factor of seven after nitrogen plasma treatment by NH3 gas with subsequent post-annealing. The full-width at half-maximum of 1.53 μm emission peak increases from 7.5 to 12.9 nm compared with that of the untreated one. Nitrogen plasma treatment is assumed to tailor Er3+ local environment, increasing the oscillator strength of transitions and thus the excitation/emission cross-section.