Al-Nanoparticle Sensitized -Ga₂O₃-BasedSolar-Blind Photodetector Fabricated viaFocused Ion Beam Micro/Nano Processing

The performance of beta-Ga2O3-based solar blind photodetector (PD) has been enhanced apparently by utilizing the effects of localized surface plasmon resonance of Al nanoparticles (Al NPs) array. The size and period of the Al NPs array are determined using the finite-difference time-domain method to obtain optimal resonance absorption with beta-Ga(2)O(3)in the solar-blind waveband. Al NPs were then fabricated using focused ion beam micro/nano processing on a beta-Ga2O3-based metal-semiconductor-metalstructure PD. The dark current of the beta-Ga2O3 structure with Al NPs (beta-Ga2O3@Al) is 7.72x10(-12)A, which is two orders of magnitude lower than that of pure beta-Ga2O3(8.01x10(-10)A). This difference is attributed to the partial oxidation of the Al NPs, which forms Al2O3 and passivates the beta-Ga(2)O(3)interface. In addition, due to the resonance absorption and the hot electrons generated by the inter-band transition of the Al NPs, the light current increases three fold, resulting in the beta-Ga2O3@Al NP PD having a highlight-to-dark current ratio of 5.57x10(4). Under a bias of 20 V and 254-nm illumination (44.38 mu W/cm(2)), the beta-Ga2O3@AlNP PD has high responsivity and detectivity of 131 A/W and 7.17x10(14) Jones, respectively. Furthermore, owing to the oxide shell Al2O3 passivation and the surface plasmons of the Al NPs, the persistent photoconductivity exhibited by the pure beta-Ga2O3 at rise time is suppressed and the decay time is sped up.