Thermal conductivity measurements of nitrogen-doped Ge2Sb2Te5

The thermal conductivity of nitrogen-doped Ge2Sb2Te5 (N-GST) was analyzed using Frequency Domain Thermoreflectance (FDTR). The thermal conductivity of amorphous N-GST (∼0.15 W/m-K) was not found to change significantly as the nitrogen concentration was raised from 0 at% to ∼6 at%, possibly due to the huge amount of phonon scattering in the disordered films. The thermal conductivity of crystalline N-GST films was found to increase initially with increasing N content, but then to decrease upon further N addition. X-ray diffraction spectra of N-GST films show increasing defect density that correlates with the decrease in thermal conductivity of the crystalline films at higher nitrogen content.