Synchrotron radiation excited luminescence of Eu, Er, and Tm codoped β-Ga₂O₃ thin film

Ga2O3 thin film with Eu, Er, and Tm codoping was prepared on Si substrate by pulsed laser deposition. The obtained codoping film has a monoclinic Ga2O3 structure identified by X-ray diffraction and Raman measurements. The excitation wavelength-dependent photoluminescence measurements were performed using synchrotron radiation sources with photon energies both below and above bandgap. Moreover, temperaturedependent PL measurements were carried out from 30 to 300 K to systematically investigate the PL characteristics of codoped Eu3+, Er3+, Tm3+ ions in the Ga2O3 film. Typical luminescent bands originating from Eu3+, Er3+, and Tm3+ dopants were concurrently observed in the PL spectra. The codoping film emits a near purple light when it was excited at 30 K, which gradually shifts to the orange region as the temperature rises to 300 K. This color evolution results from different quenching rates of Eu3+, Er3+, and Tm3+ dopants with the increase of temperature. These findings provide a solid foundation for Si-compatible full-color displays using RE doped Ga2O3.