Faculty Candidate Seminar

Growth, Characterization and the Impact of Wide-Bandgap Materials on Electronic Devices

Elaheh AhmadiPostdoctoral ResearcherUniversity of California, Santa Barbara

The ever expanding nexus of communication, computation, conservation and sensing is changing every aspect of human life. Wide bandgap materials such as (Al,Ga,In)N and oxides including the newly emerging Gallium Oxide family are playing an increasing role in providing critical solutions. For example, GaN-based LEDs and lasers are changing solid state lighting and displays, GaN-based power electronics is minimizing loss in power conversion applications such as Photo-Voltaic inverters, on-board chargers for Electric Vehicles (EV), data servers and gaming power supplies.
In this talk I will present the properties of wide bandgap materials that make them so attractive for a myriad applications and the work I have done to further the state-of "“the-art of science and technology. In particular, I will focus on N-polar GaN which has provided a major breakthrough in mm-wave high electron mobility transistor (HEMT) performance with an exceptional output power of ~7W/mm at 94 GHz, potentially providing another pathway to bridging the Terahertz gap. Controlling the quality of materials grown by MBE will be highlighted. I will explain how modeling of electron transport in two dimensional channels can be used to design next generation HEMTs and demonstrate our success doing so. I will close with detailing progress on the emerging material system of Gallium Oxide which has a bandgap of 4.8eV and promises to provide the next level of performance after GaN. Growth of Gallium Oxide and Aluminum Gallium Oxide by MBE, doping and characterization of diodes as well as solar blind UV detectors will be presented.

Elaheh Ahmadi received her BSc and MSc degrees in Electrical Engineering from Sharif University of Technology, Tehran in 2008 and 2010, respectively. She earned her PhD in Oct of 2015 from the ECE department at University of California Santa Barbara (UCSB), working on the growth and characterization of (In,Ga,Al)N-based electronic devices. After graduation she joined Materials department at UCSB as a post-doctoral researcher, working on the growth and characterization of β-Ga2O3 for high power and sensing applications. Her research interests include Epitaxial growth and characterization of III-N and Oxide semiconductor materials for electronic and optoelectronics devices, sensing and MEMs applications as well as electron transport modeling.

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