Switchable two-color electroluminescence based on a Si metal-oxide-semiconductor structure doped with Eu

A Si metal-oxide-semiconductor (MOS) electroluminescent device structure is reported which emits two colors, while being doped with a single rare-earth element. Thermally grown SiO2 oxide layers were implanted with Eu and subseqently annealed. Depending on the electrical excitation current, the luminescence is red or blue, which can be ascribed to electronic transitions in tri- and di-valent europium (Eu3+ and Eu2+), respectively.