Design of bifunctional phase-change device for storage memories and reconfigurable metasurfaces

Herein, we design an optoelectronic device using phase-change materials (PCMs) and assess its ability to possess two functionalities: the perfect absorption of photonic metasurfaces and the high-density storage capability of electronic memories. Both functionalities are evaluated experimentally and via simulations. Such bifunctionalities are achieved according to the phase-transformation extent of the designed hybrid that comprises a phase-change stack having Si/SiO2/Au/Ge2Sb2Te5 (GST)/indium tin oxide (ITO) and a conductive PtSi probe. The use of PCM layers either in a full crystalline or an amorphous phase causes perfect absorption. The resonant wavelength of the device can be dynamically changed by modulating the phase-change extent of the PCM layer. Generating a continuous crystalline region or separated crystalline bits inside the amorphous GST exhibits a larger tuneability of the phase-change extent than forming separated amorphous bits inside the crystalline GST, and allows for a wider bandwidth of 300 nm for perfect absorber applications. Forming amorphous bit array inside crystalline background yields discernible optical reading contrast when compared to forming a crystalline it array. The amorphous bit array configuration has an areal density of similar to 500 Gbits/inch(2), data rate of 5 Mbits/s, and energy consumption of 92 pJ/bit. These values render the configuration attractive for probe storage applications. Such a designed hybrid with the ability to process data photonically and store data electronically exhibit its promising for highly integrated metasurface and superb compact electro-optical computing device.

Automated summary

In this study, an optoelectronic device using phase-change materials (PCMs) was designed to demonstrate its perfect absorption characteristics and high-density storage capability. Both functionalities were evaluated experimentally and through simulations. The phase-change extent of the PCM layer was found to dynamically change the resonant wavelength of the device, allowing for perfect absorption. The use of amorphous bit arrays within a crystalline background showed promising potential for probe storage applications.