Nitrogen‐Doped GeSe_1−<i>x</i>Te_<i>x</i> Chalcogenide Thin Films: A Candidate for On‐Chip Low‐Loss Reconfigurable Photonics and Nonlinear Device Applications

Herein, the linear and nonlinear optical properties, together with the remarkable thermal stability and structural properties of thin films of nitrogen‐doped GeSe 1− x Te x chalcogenide materials, are unveiled. These alloys are obtained by reactive magnetron cosputtering technique in a 300 mm wafer industrial tool, and they are promising candidates for high‐temperature nonvolatile resistive memories due to unprecedented crystallization temperatures among all known congruent phase‐change materials (PCMs). Besides, their uncommon optical properties, measured by spectroscopic ellipsometry, make them highly attractive candidates for reconfigurable and nonlinear photonic applications in the infrared range. They exhibit a reversible phase transformation between the amorphous and crystalline phases, displaying an unprecedented contrast in electronic and optical properties between these two phases. Unlike most known PCMs, they maintain high transparency in the mid‐infrared range in both phases. By tailoring nitrogen and tellurium contents in N‐doped GeSe 1− x Te x thin films, it is shown here how it becomes feasible to customize the linear/nonlinear optical properties and thermal stability of such PCM thin films, enabling their optimization for various future optical and photonic applications.