1/25/2017 Jonathan Lin, MNTL 4 min read
Written by Jonathan Lin, MNTL
The National Science Foundation (NSF) announced that ECE ILLINOIS Assistant Professors Can Bayram and Wenjuan Zhu have earned 2017 NSF CAREER Awards, which will provide each of them with $500,000 over the next five years in support of their research and educational activities. NSF CAREER Awards empower promising junior faculty to build a firm foundation for a lifetime of leadership through integrating research and education.
Cubic Phase Green Light Emitting Diodes for Advanced Solid State Lighting
Bayram is using his award to explore the fundamental properties of cubic phase light emitting diodes (LEDs) that will provide the critical knowledge required to close the "green gap" in the visible spectrum. Current commercial LEDs consist of a mixture of red, green, and blue LEDs to produce white spectrum light. Red and blue LEDs do not rely on phosphor-down conversion, however, conventional green LEDs do, limiting green light output power only to a fraction of its theoretical limit.
Hence, this “green gap” bottlenecks efficient solid-state lighting (SSL). Eliminating this spectral gap by adjusting the fundamental properties of InGaN-based green LEDs will allow for true white LEDs – the holy grail of solid-state lighting – and lead to a new generation of high-performance, energy-efficient lighting era.
By exploiting the hexagonal-to-cubic phase transition as well as an inexpensive, scalable silicon platform, Bayram will establish a new paradigm in the understanding of phosphor-free green LEDs. To do this, his team will explore the structural mechanisms governing cubic phase material formation by identifying critical substrate nano-pattern designs that maximize cubic phase content.
Cubic phase LEDs have a smaller band gap and zero polarization, which reduces the necessary indium content and quadruples potential light output for green emitters. The knowledge to be gathered throughout this CAREER grant will enable novel photonic devices based on cubic (In)GaN technology with superior power, efficiency, speed, and bandwidth. These improvements will have significant societal and technological impact, especially in the energy, communication, and healthcare industries.
In parallel to the research activities, Bayram will develop a solid-state lighting theme-based interactive K-12 outreach program and new curriculum materials for middle schoolers and undergraduates. Bayram will make these educational resources available online to enable a significant global reach. He has already created a new ECE course titled “LEDs and Solar Cells”, being offered in the Spring 2017 semester.
Transforming Electronic Devices Using Two-dimensional Materials and Ferroelectric Metal Oxides
Next generation information technology is driving the need for integrated circuits, devices, and architectures to process unprecedented amounts of real-time data in increasingly efficient and cost-effective manners. Wenjuan Zhu’s research seeks to establish fundamental knowledge of a new hybrid material platform that consists of novel ferroelectric metal oxides (hafnium and zirconium oxide), stacked with a layer of two-dimensional material like graphene and mono/di-chalcogenides.
The ferroelectric metal oxides provide programmable and non-volatile doping in 2D materials, while the atomically thin bodies in 2D materials enable strong electrostatic control over the channel by the ferroelectric metal oxides. This new hybrid material platform will be used to create energy-efficient logic (2D Fe-TFETs), memory (2D FHOT), and analog devices (EGGFTs) that can be layered in various ways to produce novel 3D integrated systems, forming the basis for next generation circuit architecture.
Zhu’s research is the first systematic study of 2D materials on the newly discovered ferroelectric hafnium and zirconium oxides, which when compared to traditional perovskite materials, have excellent scalability, higher coercive field, as well as full compatibility with industry standard CMOS technology.
By elucidating the device physics and evaluating the future potential of these 2D ferroelectric devices, Zhu will be laying the foundation for the next generation of highly parallel, ultra-low power integrated systems. Zhu’s research comes at a time when the processing speed of integrated circuits is becoming increasingly constrained by the atomic-level physical limitations of traditional semiconducting materials. If successful, her research will be transformative in areas ranging from wearable electronics to energy efficiency computing systems for “Big Data” applications.
On the educational front, Zhu is creating a new graduate/undergraduate course on 2D materials to train the next generation workforce in nano-electronics. She also plans to implement a science education program for elementary students called “Little Einstein” and middle school girls called “Girls Go Tech” that focuses on cultivating their passion and interest in a future career in STEM fields.