Infrared photoluminescence from Er-doped a-GaAsN alloys

Amorphous gallium–arsenic–nitrogen (a-GaAsN) films were deposited by co-sputtering from a crystalline GaAs wafer partially covered with metallic Er pieces. The films were deposited at room temperature under different partial pressures of Ar and N2. After deposition, measurements of optical transmission in the visible–ultraviolet (VIS–UV) energy range, photoluminescence (PL) in the infrared (IR) region, and Raman scattering spectroscopy were made. Compositional analysis was also performed indicating an Er content of ∼0.5 at.% and a N concentration that scales with the N2 partial pressure during deposition. According to the experimental results, larger N content samples have larger optical band-gaps and more intense Er-related PL signals at 1540 nm. This dependence is analyzed in terms of the compositional, electronic and structural properties of each film.