Howgate, J. D.; Hofstetter, M.; Schoell, S. J.; Schmid, M.; Schaefer, S.; Zizak, I.; Hable, V.; Greubel, C.; Dollinger, G.; Thalhammer, S.; Stutzmann, M.; Sharp, I. D.: Ultrahigh gain AlGaN/GaN high energy radiation detectors. Physica Status Solidi A 209 (2012), p. 1562-1567
10.1002/pssa.201228097
Abstract:
Due to its remarkable tolerance to high energy ionizing radiation, GaN has recently attracted attention as a promising material for dosimetry applications. However, materials issues that lead to persistent photoconductivity, poor sensitivity, and requirements for large operational voltages have been hurdles to realization of the full potential of this material. Here we demonstrate that the introduction of a two-dimensional electron gas channel, through the addition of AlGaN/GaN heterointerfaces, can be used to create intrinsic amplification of the number of electrons that can be collected from single ionization events, yielding exceptionally large sensitivities in ultralow dose rate regimes. Furthermore, anomalous photo-responses, which severely limit response times of GaN-based devices, can be eliminated using these heterostructures. Measurements using focused monochromatic synchrotron radiation at 1–20 keV, as well as focused 20 MeV protons, reveal that these devices provide the capability for high sensitivity and resolution real time monitoring, which is competitive with and complementary to state-of-the-art detectors. Therefore, AlGaN/GaN heterostructure devices are extremely promising for future applications in fields ranging from high energy physics to medical imaging.