GaN devices have enabled a technological revolution through their success in electronic and optoelectronic applications in the last two decades. Even greater benefits to technology and society are possible if the unique material properties of the III-Nitride semiconductor system, such as the large direct band gaps and high breakdown field, are fully harnessed. However, fundamental properties of III-Nitride materials such as low electron velocity and poor p-type doping limit III-Nitride devices. To overcome these limits, new device structures that exploit quantum transport, polarization engineering, and novel material combinations are needed. The seminar will describe some such unconventional devices being developed in our group for electronics and optoelectronic applications. The first part of the seminar will describe our work on achieving vertical GaN transistors for high frequency applications, focusing first on tunneling hot electron transistors (THETA) that use ballistic transport , and then on hybrid 2D/3D semiconductor heterojunction devices that combine layered 2D semiconductors with wide band gap semiconductors . The second part of the seminar will focus on recent work on record low-resistance interband tunnel junctions to enhance the performance of GaN optoelectronic devices in the visible  and ultraviolet regimes .
Biography: Siddharth Rajan is Associate Professor in the Electrical and Computer Engineering and Material Science and Engineering departments at The Ohio State University, where he joined the faculty in 2008. He received his undergraduate degree in Physics and Electrical Engineering in 2001 from Birla Institute of Technology and Science, Pilani, India, and his PhD in Electrical and Computer Engineering in 2006 from University of California, Santa Barbara. He has held research positions in UC Santa Barbara and GE Global Research, NY. His research interests include semiconductor devices and materials, molecular beam epitaxy, transport and heterostructure phenomena, and high frequency transistors. He has co-authored over 90 journal papers and holds 5 patents in these areas of research. www.ece.osu.edu/~rajan