Modeling Electrical Switching of Nonvolatile Phase-Change Integrated Nanophotonic Structures with Graphene Heaters
Jiajiu Zheng1, Shifeng Zhu2, Peipeng Xu3
1Department of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98195, United States.
ACS Applied Materials & Interfaces
|April 17, 2020
Summary
Graphene heaters enable fast, energy-efficient switching in phase-change material photonic integrated circuits (PICs). This breakthrough overcomes limitations of current designs, paving the way for large-scale, programmable electronic-photonic systems.
Area of Science:
- Integrated nanophotonics
- Materials science
- Device physics
Background:
- Current photonic integrated circuits (PICs) face challenges in reconfigurability, energy consumption, and footprint due to reliance on weak thermo-optic/electro-optic effects.
- Chalcogenide phase-change materials (PCMs), like Ge2Sb2Te5 (GST), offer significant optical contrast and non-volatile switching, but scalability in PCM-based PICs is limited by actuation methods.
- Existing thermal-conduction heating methods for PCMs lack fast and energy-efficient electrical control, hindering large-scale integration.
Purpose of the Study:
- To model and analyze electrical switching of GST-clad-integrated nanophotonic structures using graphene heaters.
- To investigate the potential of graphene heaters for fast and energy-efficient thermal-conduction actuation in PCM-based PICs.
- To evaluate the performance of graphene heaters compared to traditional materials like indium tin oxide and silicon p-i-n.
Main Methods:
- Utilized a computational model for electrical switching of GST-on-silicon nanophotonic structures.
- Incorporated graphene heaters, leveraging their low heat capacity and high thermal conductivity.
- Simulated phase transitions and optical modulation characteristics (attenuation and phase shift).
Main Results:
- Achieved high switching speeds of approximately 80 MHz.
- Demonstrated exceptional energy efficiency: 19.2 aJ/nm3 for crystallization and 6.6 aJ/nm3 for amorphization.
- Obtained strong optical modulation with significant attenuation (~6.46 dB/μm) and phase shift (~0.28 π/μm at 1550 nm).
- Graphene heaters showed a two-orders-of-magnitude improvement in figure of merit compared to ITO and Si p-i-n heaters.
Conclusions:
- Graphene heaters offer a viable solution for fast, energy-efficient, and scalable electrical control of phase-change materials in PICs.
- The proposed GST-on-silicon platform with graphene heaters significantly enhances performance metrics for nanophotonic devices.
- This research supports the development of advanced, large-scale, programmable PCM-based electronic-photonic systems on a chip.
