High Endurance Phase-Change Devices for Electrically Reconfigurable Optical Systems

用于电可重构光学系统的高耐久性相变器件

• 批准号: 2028624
• 负责人: Nathan Youngblood
• 金额: $ 38万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2028624&HistoricalAwards=false
• 关键词: Endurance; Phase; Change; Devices; Electrically

Award Title:High-endurance phase-change devices for electrically reconfigurable optical systemsNon-Technical Abstract:Materials whose optical properties can be tuned electrically are essential to operations of many modern technologies that we rely on daily, for example, smartphone displays and fiber internet. For emerging applications in tunable optical components, high-speed computing, and advanced optical storage, a group of materials that can be reconfigured at the atomic level, known as “phase-change materials,” is particularly promising. When their atoms are arranged in either an ordered or disordered state, these materials exhibit a dramatic, stable, and reversible change in their optical properties, which could enable devices with very compact form-factor, low energy consumption and insensitivity to vibration. While many proof-of-concept optical devices have been demonstrated using phase-change materials, few can be controlled using electrical signals—a prerequisite for real world implementation. Additionally, these electrically controlled phase-change devices have shown poor endurance and switching cyclability, the cause of which is not well understood. The team proposes to address this challenge by first investigating the role of heat and mechanical expansion in the various layers comprising these devices using time-dependent optical and electrical measurements. Secondly, the team will use high resolution imaging techniques to study the role that migration of various types of atoms has on the reversibility of the phase-change material. Finally, the team will use these results to construct phase-change devices with improved reliability and explore the possibility of scaling them up to sizes needed for applications requiring larger tunable optical components. The team seeks to educate middle-/high-school students on topics related to novel materials in daily life from school districts with historically serving under-represented minorities, using a combination of interactive workshops and hands-on demos. This project also provides training for two graduate students in advanced device fabrication and characterization techniques, and hosts undergraduates from underrepresented groups during the summer months to broaden participation in STEM-related fields.Technical Abstract:Phase-change materials, such as Ge2Sb2Te5 and GeTe, are particularly promising for reconfigurable optical devices owing to their fast, dramatic, non-volatile, and reversible change in refractive index. Experimental demonstrations of reconfigurable smart windows, reflective displays, metasurfaces, and photonic devices for memory and computing have re-ignited interests in these materials. For phase-change devices with dimensions greater than the optical wavelength, an electro-thermal approach to switching is most promising, but limited prior work showed poor endurance and cyclability (1000 cycles or less) compared to the high endurances (greater than 10 million cycles) demonstrated for phase-change data storage. The team proposes that the endurance is limited by poorly matched thermal properties of materials within these devices, while the degrading optical contrast often observed is due to phase segregation and void formation in the phase-change layer. To validate this hypothesis, the project has three aims: (1) improve the lifetime of electro-thermal phase-change devices by properly matching the thermal expansion coefficients of the materials within the device layers; (2) reduce the cycling-induced degradation of optical contrast by reducing thermal gradients within the device and improving deposition conditions; and (3) identify the effects and limitations of scaling on phase-change optical devices. The proposed approach will overcome the limited cyclability of these electro-thermally switched phase-change devices by studying the thermal response of the device layers through complementary thermal-mechanical modelling, dynamic optoelectronic measurements, and advanced nano-characterization techniques. The insights gained by understanding and addressing the current limitations of electro-thermally controlled optical phase-change films are expected to be broadly applicable to such fields as tunable optical coatings, non-von Neumann computing, electrical-optical conversion, and reconfigurable photonic and RF systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

奖励标题：用于电子可重新配置的光学系统的高含量相变设备NON-TECHNICAL摘要：可以在电气上对光学性质进行电气调整的材料对于我们每天依赖的许多现代技术的操作至关重要，例如，智能手机显示器和光纤互联网。对于可调光学组件，高速计算和高级光学存储中的新兴应用，可以在原子水平重新配置的一组材料（称为“相变材料”）尤其有前途。当它们的原子以有序或无序状态排列时，这些材料的光学性质会出现戏剧性，稳定和可逆的变化，这可以使设备具有非常紧凑的形式因素，低能消耗和对振动不敏感的设备。尽管已经使用相位变换材料证明了许多概念验证的光学设备，但很少使用电信号来控制现实世界实施的先决条件。此外，这些电气控制的相位变换设备显示出耐耐受性和切换性可环性，其原因尚不清楚。团队提出的建议是通过首先研究使用时间依赖的光学和电气测量的各个层中热量和机械扩张的作用，以应对这一挑战。其次，团队将使用高分辨率成像技术来研究各种原子的迁移对相变材料的可逆性的作用。最后，团队将使用这些结果来构建具有提高可靠性的相变设备，并探索将它们扩展到需要更大可调光学组件所需的尺寸的可能性。该团队旨在教育中/高中生就学区的日常生活中新型材料相关的主题教育，历史上有代表性不足的少数群体，结合了互动式研讨会和动手演示。该项目还为两名研究生提供了高级设备制造和表征技术的培训，并在夏季几个月内从代表性不足的群体的本科生提供了本科生，以扩大与STEM相关的领域的参与。技术摘要：GE2SB2TE5和GETE（例如GE2SB2TE5和GETE），尤其是在尚有依据的依据，以使他们的恢复良好的依据，并在其上进行了反复变化。折射率。可重新配置的智能窗口，反射显示，元图和计算机设备的实验演示具有对这些材料的重新点燃兴趣。对于尺寸大于光波长的相变设备，与高耐力（大于1000万个循环）相比，对相位转换数据存储的高耐力（大于1000万个循环）相比，开关的电热方法是最有限的。团队提出的耐力受到这些设备内材料的热性能较差的限制，而降解的光学对比度通常是由于相位分离和相变层中的空隙形成所致。为了验证这一假设，该项目具有三个目的：（1）通过正确匹配设备层中材料的热膨胀系数，改善电热相变设备的寿命； （2）通过减少设备内的热梯度并改善沉积条件，减少了循环引起的光学对比度降解； （3）确定缩放对相变光学设备的影响和局限性。所提出的方法将通过完成完整的热机械建模，动态光电测量和晚期纳米特征化技术来研究设备层的热响应，从而克服这些电流切换的相变设备的有限循环性。通过理解和解决电流控制的光学相位变化膜的当前局限性获得的见解，预计将广泛适用于可调的光学涂料，非伏诺曼计算，电气转换，电气转换，电气转换，以及通过nsf of Sutportional的授权和RF的重新配置，并反映了NSF的裁定，并反映了NSF的构建奖。更广泛的影响审查标准。

项目成果

AnalogVNN: A fully modular framework for modeling and optimizing photonic neural networks

• DOI: 10.1063/5.0134156
• 发表时间: 2022-10
• 期刊: ArXiv
• 作者: Vivswan Shah;N. Youngblood

Comparing the thermal performance and endurance of resistive and PIN silicon microheaters for phase-change photonic applications

• DOI: 10.1364/ome.488564
• 发表时间: 2023-05
• 期刊: Optical Materials Express
• 影响因子: 2.8
• 作者: John R. Erickson;Nicholas A. Nobile;D. Vaz;Gouri Vinod;Carlos A. Ríos Ocampo;Yifei Zhang;Juejun Hu;S. Vitale;Feng Xiong;N. Youngblood

Nonvolatile Tuning of Bragg Structures Using Transparent Phase-Change Materials

使用透明相变材料对布拉格结构进行非易失性调谐

• 发表时间: 2023
• 期刊: Optical materials express
• 影响因子: 2.8
• 作者: Nicholas A Nobile, Chuanyu Lian

Nonvolatile band switching using transparent phase-change materials on Bragg structures

在布拉格结构上使用透明相变材料进行非易失性能带切换

• DOI: 10.1117/12.2647868
• 发表时间: 2023
• 期刊: and Technologies XXVII
• 作者: Nobile, Nicholas A.;Lian, Chuanyu;Sun, Hongyi;Mills, Brian;Popescu, Cosmin Constantin;Hu, Juejun;Ríos, Carlos;Youngblood, Nathan
• 通讯作者: Youngblood, Nathan

Designing fast and efficient electrically driven phase change photonics using foundry compatible waveguide-integrated microheaters

• DOI: 10.1364/oe.446984
• 发表时间: 2022-04-11
• 期刊: OPTICS EXPRESS
• 影响因子: 3.8
• 作者: Erickson, John R.;Shah, Vivswan;Xiong, Feng
• 通讯作者: Xiong, Feng