Low-Power Phase Transition of Chalcogenide Glass Using Au Nanoparticle Plasmon Resonance

摘要

Chalcogenide materials are attractive for all-photonic phase-change memories owing to their large optical contrast between amorphous and crystalline structural phases. However, high-power heating pulses are required to switch these structural phases, which can limit the cyclability. To reduce power, Au nanoparticles (NPs) are embedded in a typical chalcogenide phase-change material, Ge2Sb2Te5 (GST). Raman analysis shows that a GST film crystallizes at a low optical power of 2 mW, which is almost 10 times lower than that of materials not embedded with NPs. This lower power is owing to the enhanced light absorptance through the strongly localized surface plasmon resonance (LSPR) of the Au NPs. The Au NPs embedded in the GST film scatter light at lambda = 587 nm, which is close to Au NP's LSPR of approximate to 535 nm. Laser light at 532 nm is used to measure Raman scattering from the Au-GST system. The Raman scattering is enhanced by a factor 12 compared with a bare GST film. This study indicates that the GST film-Au NP system is suitable for high-speed, low-power, phase-change memory and for a new type of tunable surface-enhanced Raman scattering substrate.