The development of terahertz sources and detectors is the subject of extensive research efforts, as these devices could enable numerous high-impact applications in the areas of sensing, spectroscopy, and imaging. GaAs-based THz devices have made substantial progress recently; however they can only provide incomplete spectral coverage and remain limited to cryogenic temperatures due to an intrinsic property of GaAs, namely the presence of LO phonons with THz-range frequencies. To overcome these limitations, the PIs propose to develop intersubband THz sources and photodetectors using GaN/AlGaN quantum wells, which feature LO-phonon frequencies well outside of the THz region.
Intellectual merit: The argument of using nitride quantum wells for THz device development is very compelling and has been substantiated by detailed theoretical studies. The research objectives will be pursued with a combination of material development efforts, Monte Carlobased design studies, and device processing optimization, and all the required resources and expertise are available. This work will also advance the general state of knowledge in the area of nitride heterostructures and related devices.
Broader impacts: The proposed activities will promote education through the training of students in a variety of disciplines, ranging from epitaxial growth, to quantum engineering, computational electronics, and THz photonics. To increase the program effectiveness and scope, the involvement of undergraduates, high-school interns, and students from disadvantaged backgrounds is also emphasized. Finally, the proposed devices have the potential for a revolutionary impact in several technology areas of high relevance, such as security screening,manufacturing quality control, and medical diagnostics.
