SBIR-STTR Award

With its wide band gap allowing high voltages, high currents, and high temperatures, compensated gallium nitride (GaN) is a good candidate for constructing optically triggered switches that can operate at high voltage, current, and temperature. To achieve high responsivity GaN-based switches are often triggered with above bandgap photons, which are difficult to obtain at sufficient fluxes and in small packages with current technologies. This proposed work will integrate a compensated In-containing channel layer to the PCSS device in order to slightly shift the bandedge and take advantage of widely available and powerful blue laser diode sources. The devices are targeted to operate at >150 C and will be designed to hold off 1200 - 2000 V, while supplying 10 - 120 A. A responsivity of at least 0.5 A / W at 1200 V is anticipated.

This effort seeks to develop a novel wide bandgap photoconductive semiconductor switch capable of operating at >150 deg C that can hold off 1200–2000 V while supplying 10–120 A for applications in electro-hydrostatic and electro-mechanical actuator motor drives for air platforms. As a follow-on from Phase I efforts, this Phase II project proposes to optimize photoconductive gallium nitride (GaN) devices, in a vertical geometry, to meet the voltage and current requirements. Photoconductive GaN has demonstrated very high photoresponsivity with sub-gap excitation, allowing high current output with an inexpensive, compact, low-power, 405 nm laser diode. The scope of work includes optimizing GaN material doping and device geometry (substrate, thickness, area, contact geometry) with characterization of continuous and dynamic optical response, in addition to high-temperature behavior, culminating in the demonstration of a prototype small-form-factor optical switching device package. Material growth, device fabrication, and prototype design/build will be completed by the lead, Kyma, and the majority of optical–electrical testing, with supporting simulation efforts will be completed at UMKC (subcontractor).