Deep UV photoluminescence studies of Lutetium (III) Oxide

Lutetium (III) oxide (Lu₂O₃) is an ultra-wide bandgap (5.5 - 5.9 eV) semiconductor that could have potential applications in optical devices operating in deep ultraviolet (UV) region. Deep UV photoluminescence (PL) spectroscopy was employed to study the optical properties of thin film and crystal powder Lu₂O₃ samples using the fourth harmonic laser (~195 nm) generated from a Ti: sapphire laser for optical excitation. Low temperature (8 K) PL spectra of the samples annealed at 800 ^oC for 1 hour in oxygen have dominant emission peak around 4.85 eV. Additionally, we observed weak PL emissions in deep UV region at 5.50 and 5.74 eV which we assumed to be band-edge emissions. The powder sample also has an emission peak at 3.61 eV. We will present the effect of annealing temperature on the PL, and power- and temperature-dependent PL measurements of the annealed Lu₂O₃ samples. We will discuss the energy diagram of Lu₂O₃ based on the observed PL and absorption measurements. Our findings on optical properties of Lu₂O₃ could have implications on its potential applications in deep UV optical devices.