| The current shortage of Helium-3 proposes a challenge for searching other neutron detection methods to fulfill the increased demand in both industry and academic research applications. Semiconductor radiation detector is one trend of this campaign due to its potential to provide portable, high detection efficiency devices. As a semiconductor material, Gallium Nitride (GaN) was recognized as one of the most promising candidates for radiation detection, especially for operating in harsh environments, mainly due to its superior properties, such as the wide band-gap, large displacement energy, and high thermal stability, etc.;In this research, sandwich structure Schottky diodes were fabricated on n-type bulk GaN substrate with thickness of ∼ 500 micrometers. The radiation response was achieved by both using 5.4 MeV alpha particles emitted from Am-241 source and a neutron converter 6LiF:ZnS foil (0.3 mm). The results are promising as a high charge collection efficiency was found. The devices were then characterized by current-voltage, capacitance-voltage, and alpha spectroscopy, and the corresponding electrical properties were derived. The major device parameters were obtained including the doping level of these wafers (∼ 1016 cm-3), the depletion region depth (several micrometer under several volts), and the Schottky barrier height (0.75 eV). In addition, high temperature current-voltage characteristic and the neutron radiation effect were studied to investigate GaN sensor's potential application in harsh environment. Furthermore, simulation was performed by Sentaurus TCAD to understand the charge collection process within these detectors. This research provides some insights on future study of using GaN for radiation detection applications. |
