Ternary and quaternary Ge-S-Se-Sb-Te amorphous chalcogenide thin films for mid-infrared applications

Chalcogenide materials exhibit a unique portfolio of properties which has led to their wide use for nonvolatile memory applications such as optical storage (CD-RW and DVD-RAM), Conductive Bridging Random Access Memory or Phase Change Random Access Memory (PCRAM). More recently, thanks to huge electronic nonlinearities under electrical field application, chalcogenide glasses are considered as most promising materials to be used as Ovonic Threshold Switching (OTS) selectors [1]. Besides, thanks to high transparency window in the infrared range and large optical nonlinearities [2], chalcogenide alloys offer the opportunity of development of innovative mid-infrared (MIR) components such as MIR supercontinuum (SC) laser sources, optical sensors, IR micro-lens arrays and all-optical integrated circuits [3, 4]. Up to now, the state-of-the-art MIR supercontinuum generation on a chip or with fibres has been demonstrated with chalcogenide materials containing Arsenic such as As
₂
S
₃
[5], As
₂
Se
₃
fibres [6] or GeAsSe rib waveguide [7, 8]. However, the R.E.A.C.H. European recommendation
¹
- which calls for the progressive substitution of the most dangerous chemicals - and a recent publication from the World Health Organization
²
have both identified Arsenic as one of the ten most harmful chemicals for human health.