The effective light‐harvesting performance of graded compositional AlxGa1−xN nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation. (18th March 2020) - Liu, Lei
Summary: A graded compositional Alx Ga1−x N nanomaterial with a built‐in electric field has been proposed to improve the quantum efficiency of the negative electronic affinity photocathode. When the graded compositional Alx Ga1−x N nano‐cone array is applied to the ultraviolet (UV) detector, it is necessary to improve the effective light absorption, which is high absorption in the UV short‐wavelength and high sensitivity in the threshold wavelength. Therefore, the light absorption of nano‐cone arrays with different feature sizes and geometrical properties is accurately calculated innovatively based on the finite‐difference time‐domain method. Studies show that a non‐close‐packed six‐sided pyramid structure with a fill factor of 42.44% and a height of 1000 nm has an absorption spectrum that better satisfies the response characteristics of the UV detector. Surface reflection depends to a large extent on the transformation of the angle of incidence. The optical absorption properties of the graded compositional Alx Ga1−x N nano‐cone array provide flexibility and reference value for the improvement of the absorption coefficient and other parameters in the actual quantum efficiency experiment of the UV photocathode with built‐in electric field, which can realize the highest sensitivity of various designed UV detector optical system. Abstract : Considering its ability to generate a built‐in electric field, which could improve the quantum efficiency of the photocathode for ultraviolet (UV) detector, we introduced the graded compositional Alx Ga1−x N nanostructured array photocathode. The finite‐difference time‐domain method is used to calculate the optical absorption characteristics of the graded compositional Alx Ga1−x N nanostructured photocathode. In this study, nano‐cone arrays with three different cross‐sectional shapes were subjected to optical absorption simulation analysis, taking into account the structural factors such as fill factor, height, and angle of incidence. Studies show that a non‐close‐packed six‐sided pyramid structure with a fill factor of 42.44% and a height of 1000 nm has an absorption spectrum that better satisfies the response characteristics of the UV detector. These simulations can provide an interesting attempt for the realization of nano‐based GaN UV detector and are expected to improve the quantum efficiency performance.