The radiation effect of swift heavy ions (16MeV 181Ta) on the Au/Ni/-Ga2O3 vertical Schottky barrier diodes(SBDs) were investigated at the fluence of 1×108, 3×108 and 3×109 cm-2. The SBDs were characterized by current density-voltage (J-V) and capacitance-voltage (C-V) measurements. It was found that Schottky barrier height ϕ decreased from 1.11 eV to 0.94 eV, the ideality factor n increased from 1.01 to 1.29, turn-on voltage Von increased from 0.52 V to 0.80 V after radiation of 3×109 cm-2. The reverse breakdown voltage was decreased from -405 V to -375 V, -350 V and -255 V after radiation of 1×108, 3×108 and 3×109 cm-2, respectively. In addition, the carrier concentration calculated from the capacitance-voltage curves was decreased significantly. Based on the G/ω-ω measurement results, the trap density at the Ni/β-Ga2O3 interface was extracted to be 2.89×1015-2.49×1016 cm-2∙eV- 1 and 2.18×1015-4.98×1016 cm-2∙eV-1 with the energy level of 0.85~0.87eV below the conduction band edge.
AlGaN-based ultraviolet-A light-emitting diodes (UVA LEDs) inevitably suffer from current crowding effects at high injection levels due to their lateral device structure, resulting in non-uniform light emission and device overheating. In Npolar UV LEDs, the problem is further exacerbated by increased hole injection efficiency, leading to current crowding and aggravated hole leakage, which limits the device performance. An n-AlGaN/AlInGaN/AlGaN structure is adopted in this study, through modulation of the Al and In compositions in the AlInGaN quaternary alloy, lattice matching and greater bandgap of AlInGaN to AlGaN template is designed. The numerical results prove that the n-AlGaN/AlInGaN/AlGaN structure can promote current spreading and thus mitigate hole leakage, resulting in the significantly enhanced performance of N-polar UVA LEDs. Furthermore, the use of lattice-matched AlInGaN layers in practical epitaxy is feasible, which can avoid the defect introduction resulting from the lattice mismatch.
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