Cathodoluminescence from Y2O3:Er3+: A metal oxide-based green nanophosphor for field emission displays

The degradation of Y2O3:Er3+ nanophosphors under cathodoluminescence (CL) was assessed for their suitability as a green phosphor for low-voltage field emission displays (FEDs). The Er3+-doped Y2O3 green nanophosphor was prepared using the solution combustion approach and characterized by x-ray powder diffraction (XRPD) and photoluminescence (PL) spectroscopy. XRPD analysis indicated a single-phase cubic Y₂O₃ structure. Under UV excitation at 378 nm, the PL spectra showed a strong green emission corresponding to the 4S3/2 → 4I15/2 transition of the Er3+ ions. Green luminescence and degradation in Y2O3:Er3 nanophosphors were studied using a 2 kV, 3 μA electron beam in vacuum. Auger electron spectroscopy (AES) was used to analyze the surface chemical modification of nanophosphors after achieving a vacuum pressure of 2.6 × 10−8 Torr. The CL degradation of nanophosphors was investigated by simultaneously monitoring the CL and Auger electrons’ peak-to-peak heights with an electron dose of 932 C/cm2. The CL intensity was then correlated with surface modifications observed in the AES results. The CL spectra for different accelerating voltages (0.5–2 kV) and probe currents were also measured. A noticeable enhancement in CL intensity was detected in the powders as the accelerating voltage ranged from 0.5 to 2 kV, highlighting a crucial property for their potential application in FEDs. Under continuous low-voltage electron-beam bombardment, phosphors demonstrated outstanding resistance to degradation and maintained good color stability. These findings suggested that Y2O3:Er3+ nanophosphor is a promising candidate for green phosphors in field emission displays.