RF magnetron co-sputtered amorphous Ge-Bi-Se chalcogenide films for photonics application

We examined the potential of amorphous Ge-Bi-Se chalcogenide films prepared from RF magnetron co-sputtering.(Co)-sputtered films’ compositions were analysed using EDX spectroscopy. Pre-deposition calculations were used to find the expected composition, and a good agreement with experimentally determined compositions were observed. The amorphous to crystalline phase change in films were closely examined by XRD analysis and Raman spectroscopy in terms of atomic % of Ge by slowly increasing the GeSe2 contribution during co-sputtering. The influence of the composition on the optical band gap energy, refractive index and transmission spectra were also analysed using variable angle spectroscopic ellipsometry(VASE) and spectrophotometry analysis from visible to mid-IR. Third-order nonlinear optical parameters of the co-sputtered films were estimated using Sheik-Bahae formalism. The ridge waveguides were fabricated from RF magnetron co-sputtered Ge-Bi-Se films on Si/SiO2 substrate to obtain single-mode waveguides at 1.55 μm.

Financial support from Czech Science Foundation and European Union’s Horizon Europe Framework Programme under grant agreement No 101092723 is greatly acknowledged.