University of Michigan, Electrical Engineering & Computer Science
Abstract: Gallium nitride (GaN) semiconductors are best known for their revolutionary applications in creating significant energy savings for electric lights (Nobel Prize in Physics 2014). Unlike silicon and the majority of other compound semiconductor materials, GaN is piezoelectric due to its wurtzite symmetry which is noncentrosymmetric. The piezoelectricity creates an electric potential when the material is strained. The piezoelectric potential can cause the electrons and holes to be separated from each other, which is disadvantageous to their radiative recombination efficiency. However, if properly engineered, the piezoelectric potential can enable a suite of applications for future augmented reality, robotics, health care, and quantum information technologies. In this talk, I will introduce the idea of local strain engineering which allows us to engineer the piezoelectric potential in a nanometer length scale by using the GaN nanostructures. I will discuss how the nanostructure’s geometry can be used as a tuning knob to control the optical properties of the material. A simple theoretical model will be presented that can be easily adapted for device design. I will also give a brief overview on various potential applications with the main focus on quantum photonics.
Biography: P.C. Ku received his BS from the National Taiwan University and PhD from the University of California at Berkeley, both in electrical engineering. He was awarded the Ross Tucker Memorial Award in 2004 as a result of his PhD research. He was with Intel before joining the University of Michigan where he is currently a professor of electrical engineering and computer science. In 2010, he cofounded Arborlight that was dedicated to solid-state lighting system design and application. He received the DARPA Young Faculty Award in 2010.
Lecture via Zoom