R&D: Design of Bifunctional PhaseChange Device for Storage Memories and Reconfigurable Metasurfaces

Ceramics International has published an article written by Xiaojuan Lian, College of Integrated Circuits Science and Engineering, Nanjing University of Posts and Telecommunications, NO. 9 Wenyuan Road, Nanjing, 210023, Jiangsu, PR China, and National and Local Joint Engineering Laboratory of RF Integration oand Micro-assembly Technology, Nanjing University of Posts and Telecommunications, NO. 9 Wenyuan Road, Nanjing, 210023, Jiangsu, PR China, Zhixuan Gao, Jinke Fu, Xiang Wan, College of Integrated Circuits Science and Engineering, Nanjing University of Posts and Telecommunications, NO. 9 Wenyuan Road, Nanjing, 210023, Jiangsu, PR China, Qingying Ren, Electrical & Electronic Laboratory Center, Department of Optical Engineering, College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, NO. 9 Wenyuan Road, Nanjing, 210023, Jiangsu, PR China, Xiaoyan Liu, and Lei Wang, College of Integrated Circuits Science and Engineering, Nanjing University of Posts and Telecommunications, NO. 9 Wenyuan Road, Nanjing, 210023, Jiangsu, PR China.

Abstract: “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 bit array. The amorphous bit array configuration has an areal density of ~500 Gbits/inch², 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.“