Ground-state measurement of Pr3+ in Y2O3 by photoconductivity

Abstract

1 at % Pr3+-doped Y2O3 single-crystal fibers were prepared using a laser-heated pedestal growth method. The emission and excitation spectra of the fibers were measured. The emissions of 4f-4f transitions from 1 D 2 to the 3 H 4 and 3 H 5 states are found at 620 and 720 nm, respectively. The 3 P 2, 3 P 1, 1 I 6, and 3 P 0 4f-4f absorptions are observed at 456, 472, 482, and 492 nm, respectively. A 4f-5d absorption band is detected at 288 nm. Photoconductivity measurements show that the 4f-5f transition of Pr3+ around 285 nm produces a direct photocurrent. Taking the onset of photocurrent to be at 320 nm, the ground state of Pr3+ is determined at 1.7 eV above the valence band of the host.