Tungsten-doped Ge2Sb2Te5 phase change material for high-speed optical switching devices

Abstract

The large impedance mismatch between the highly resistive amorphous state and the highly conductive crystalline state of Ge2Sb2Te5 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.