GaN/AlGaN/AlInN Based THz Focal Plane Array Detectors, Ultraviolet (UV) Lasers, and HEMT High Power RF Devices on Low-Dislocation AlN and GaN Substra

In this Phase I effort our team, a collaboration between Traycer Diagnostic Systems and The University of Notre Dame, proposes to develop a single pixel detector of terahertz frequency electromagnetic radiation. The devices we propose are AlN/GaN high electron mobility transistors which, via the excitation of plasma waves in the device channel, exhibit a nonresonant broadband and resonant response to THz radiation which considerably exceeds their operational limit as transistors. The commercial viability of these devices is critically dependent on electrical metrics such as the two dimensional electron gas mobility and channel concentration. Therefore, the growth of high quality epitaxial layers by reducing dislocations, roughness, and defect densities at the AlN/GaN heterointerface is critical to a functional device. Leveraging important results achieved at NDU on sapphire substrates, we propose developing this detector on AlN substrates based on a two part strategy which combines a materials development and characterization effort with the fabrication, broadband nonresonant, and resonant testing of individual devices in the sub-terahertz and terahertz regimes. Towards the goal of a commercially viable focal plane array, we also propose the early stage investigation of novel antenna and device architectures to achieve lower noise equivalent power measurements. BENEFIT: Traycer Diagnostic System’s (TDS) core focus is creating an imaging system for the screening and detection of epithelial or excised breast cancer. This system-level architecture involves an array of novel technologies being developed by TDS for the emission and detection of microwave and terahertz frequency radiation. The relatively low photon energies of this radiation provide significant advantages over conventional x-ray methods for cancer detection. Non-ionizing terahertz imaging can elicit dielectric contrast information and indirectly recognize the chemical composition of material under study, allowing for passive mapping of material composition for use in the high-resolution, non-destructive evaluation of biologic and non-biologic samples. The development of III-N detectors of terahertz radiation therefore directly relates to TDS’ mission in that the devices hold significant promise for THz-sensitive, tunable, focal plane arrays that have not been effectively realized with competing technologies. While the mammography market is the initial focus of TDS, high-sensitivity microwave and terahertz sensor technologies potentially address any of a number of applications of interest to the Department of Defense and other federal agencies, along with important private sector markets. Most prominently, terahertz radiation can be used in security applications such as screening individuals for weapons or contraband, satellite communications, detecting and identifying biological or chemical weapons or their residues, and non-destructive structural integrity testing. Such a multi-use technology makes this an important collaboration for all parties.