Comprehensive study on the optical properties of graded Al component Al_xGA_(1-x)n nanostructures for UV photocathode

摘要

In this paper, we numerically studied the effect of gradient Al component distribution on the optical capture performance of AlxGal-xN nanowires with various geometrical structure. Based on the finite element method COMSOL multiphysics commercial software, this paper systematically studied the influence of geometric parameters such as base radius (R), nanorod height (H), period (P) and the filling factor (FR). The simulation results show that compared with other nanostructures, the multiradius cylinder can effectively couple photons into the nanoarray to achieve a wide-band and effective light absorption of the AlxGal-xN UV photocathode. We change the distribution range of Al components (0-0.35 and 0-0.75) and the thickness of different sub-layers in the nanostructures to study their effects on the optical properties of AlxGal-xN nanostructures. Consequently, Cylinder nanoarray achieves enhanced optical absorption and quantum efficiency with gradient Al component range at 0-0.35 and graded thickness of the sublayer. In addition, we also flexible adjusted geometry of AbcGal-xN nanoarrays to obtain the most effective optical absorption for the ultraviolet detector optical system. All these findings not only indicate that the gradient Al component AlxGal -xN material has great potential advantages for UV photocathodes, but also provide a wide-band enhanced light absorption for UV photocathode.