GST Loaded SiO2 Box Resonator Fabricated on Si for Amplitude Tunable Near-IR Absorber

An amplitude tunable frequency selective near infrared (854 nm) resonant-absorber on silicon (Si) has been demonstrated here. Tunability in absorbance was obtained by means of a box-resonator which comprises of 10 nm sputter deposited germanium-antimony-telluride (GST) film over a 418 nm wet-oxidized silicon dioxide (SiO ₂ ) layer grown on Si. Outer reflective surfaces of the resonator were deposited by thermal evaporation of aluminum, over which bias pads and cavity for light entrance and collection were patterned. Fabricated resonant-absorber demonstrated 159 ± 11 % change in absorbance due to thermally induced phase change in GST, which determines strength of cavity mode in thicker SiO ₂ layer