Tungsten-doped Ge_2Sb_2Te_5 phase change material for high-speed optical switching devices

摘要

The large impedance mismatch between the highly resistive amorphous state and the highly conductive crystalline state of Ge_2Sb_2Te_5 is an impediment for the realization of high-speed electrically switched optical devices. In this paper, we demonstrate that tungsten doping can reduce this resistivity contrast and also results in a lower amorphous state resistivity. Additionally, it lowers the contact resistance, improves the optical contrast, and extends the face-centered-cubic state up to 350 °C, with a minimal impact on thermal conductivity.