Red light emission by photoluminescence and electroluminescence from Pr-doped GaN on Si substrates

Abstract
Visible light emission has been obtained at room temperature by photoluminescence (PL) and electroluminescence (EL) from Pr-doped GaN thin films grown on Si(111). The GaN was grown by molecular beam epitaxy using solid sources (for Ga and Pr) and a plasma gas source for N2. Photoexcitation with a He–Cd laser results in strong red emission at 648 and 650 nm, corresponding to the transition between P03 and F23 states in Pr3+. The full width at half maximum (FWHM) of the PL lines is ∼1.2 nm, which corresponds to ∼3.6 meV. Emission is also measured at near-infrared wavelengths, corresponding to lower energy transitions. Ar laser pumping at 488 nm also resulted in red emission, but with much lower intensity. Indium-tin-oxide Schottky contacts were used to demonstrate visible red EL from the GaN:Pr. The FWHM of the EL emission line is ∼7 nm.