Photoluminescent and electroluminescent Zn2Si0.5Ge0.5O4:Mn thin films for integrated optic devices

The optical, photoluminescent (PL), and electroluminescent (EL) properties of Zn₂Si_0.5Ge_0.5O₄:Mn (ZSG:Mn) have been studied in order to determine its viability as a light source for integrated optics systems. ZSG:Mn thin films were deposited at room temperature by RF-sputtering on Si substrates. EL devices (ELDs) were fabricated using transparent indium-tin oxide electrodes. ELDs using as-deposited ZSG:Mn films emitted bright orange light with a broad spectrum at 590-660 nm. Annealing at 700°C resulted in a color shift to green emission in a band from 510 to 550 nm and peaking at 520 nm. Ridge waveguides fabricated by induction-coupled plasma etching yielded an optical loss of 3.8 dB/cm at 633 nm. Prism coupling experiments revealed a decrease in the film refractive index as the result of the anneal. The combination of strong PL, EL, and low waveguide loss demonstrates the strong potential of transition metal- and/or rare-earth-doped ZSG as a robust light source for integrated optic systems.