Effect of N dopants on the phase change characteristics of Cr2Ge2Te6 film revealed by changes in optical properties

[Display omitted] •The microstructure, optical properties, and crystallization kinetics of N-doped Cr2Ge2Te6 phase change materials were investigated.•An inverse reflectance change behavior upon phase transition in visible light region was obtained in Cr2Ge2Te6 by doping N.•A faster crystallization speed of N-doped Cr2Ge2Te6 due to a shorter incubation time and a simplified one-step crystallization process with fast growth was confirmed.•The power required for reamorphization of N-doped Cr2Ge2Te6 is lower than that of pure Cr2Ge2Te6. In this study, the microstructure, optical properties, and crystallization kinetics of N-doped Cr2Ge2Te6 (NCrGT) phase change materials (PCMs) were investigated. The NCrGT films exhibited a reflectance decrease upon crystallization, which is opposite to the behavior of CrGT and traditional PCMs, such as Ge2Sb2Te5. Additionally, the N dopants were confirmed to accelerate the crystallization speed of CrGT. Furthermore, the crystallized spots on the NCrGT films were found to be reamorphized by laser irradiation at a lower power than is required for CrGT, indicating a reversible laser pulse-induced phase transition and a lower thermal cost resulting from the incorporation of N. The faster crystallization speed of the NCrGT films originated from their shorter incubation time and simplified crystallization process tuned by the local bonding configuration close to N atoms. Our findings demonstrate that adding N dopants can dramatically alter the optical properties of CrGT, leading to faster crystallization and reduced power consumption.