Speaker
Description
Gallium nitride (GaN) is a desirable material for charged particle spectroscopy in high temperature, high radiation environments. We report on results obtained from GaN vertical Schottky devices fabricated on 8 µm thick non-intentionally doped GaN epitaxial layers grown on native GaN substrates where the thick epi-layer is intended for ionizing radiation detection. Bulk dark current densities of 2 µA/cm$^2$ at -1 V with perimeter leakage attributed to surface effects of 4.5 nA/cm at room temperature, with an extracted Schottky barrier of 0.72 eV for a Ni/Au Schottky metal. The capacitance-voltage data reveal background doping in the low 10$^{15}$ cm$^{-3}$ range. Pulsed 355 nm UV light produces a photoresponse that increases as a function of reverse bias, with an estimated carrier collection efficiency of up to 5%. Moving the incident beam away from the Schottky contact reveals a minority carrier diffusion length up to 10 µm. However, due to the strong absorption of GaN at this wavelength, this lateral diffusion length is impacted by surface effects which conceals the bulk diffusion length. Finally, optical deep-level transient spectroscopy reveals two electron trap states at 456 and 129 meV below the conduction band with low concentrations (<1% of the doping) and capture cross-sections <10$^{-15}$ cm$^{-2}$.
| Type of presentation (in-person/online) | online presentation (zoom) |
|---|---|
| Type of presentation (I. scientific results or II. project proposal) | I. Presentation on scientific results |