Sputter deposited GaN doped erbium thin films: Photoluminescence and 1550 nm infrared electroluminescence

Erbium doped gallium nitride (GaN) thin films were deposited on Si substrates by reactive rf magnetron cosputtering of a commercial GaN target, together with a metallic erbium target. Nitrogen was employed as the reactive sputtering gas. The gallium nitride doped erbium (GaN:Er) films thus obtained, exhibited the characteristic 525, 540, 660, and 1550 nm photoluminescence emission associated with the Er+3 ion 4f–4f intraband transitions. In addition, 1550 nm IR electroluminescence (EL) emission was observed from the sputter deposited GaN:Er phosphor films. The EL device was an inverted half-stack ac thin-film EL device structure. The 1550 nm EL emission is consistent with impact excitation and subsequent I13/24→4I15/2 radiative relaxation of Er+3 ions. Impact excitation requires conduction electrons with sufficient energy from electrical field acceleration, to excite the transition.