An experimental set-up forin situHall measurements under high-energy electron irradiation for wide-bandgap materials

A dc Hall-effect apparatus, based on conventional van der Pauw specimen geometry, has been developed for in situ measurements under van de Graaff electron irradiation (0.7–2.2 MeV). An associated cryostat permits ambient temperatures of 95–300 K. A key element is a flat permanent magnet of field strength 3.55 kG. Initial test measurements have been performed on wide-bandgap semiconductor materials, including an HVPE-grown AlGaN/GaN heterostructure field-effect transistor structure.