Simulation analysis of GaN microdomes with broadband omnidirectional antireflection for concentrator photovoltaics

Abstract

Microdome structures are analyzed as surface topology to reduce surface reflection over a broad spectral range and wide light incidence angle for concentrator photovoltaics application. Three dimensional finite difference time domain method was used to accurately calculate the surface reflection and transmission for surface topologies with different feature sizes and aspect ratios. Studies show that the use of GaN microdomes will lead to a significant reduction of the surface reflection over a broad wavelength range and wide incidence angle range. The surface reflection significantly depends on the surface structure feature size and geometrical shape. The design of the GaN microdomes provides flexibility to tune the structure in order to obtain the minimum surface reflection for different designs of concentrator optical systems. The surface reflections of the GaN microdomes are compared with that of the conventional flat surface as well as the one with antireflection coating.

Surface antireflection properties of GaN nanostructures with various effective refractive index profiles

“…In this work, the numerical studies of surface antireflection properties of GaN nanostructures with various effective refractive index profiles were performed by using a 3D-FDTD method. Based on our previous studies [17], the surface reflection significantly depends on the surface structure size and shape. GaN hemi-ellipsoid microdome with dimension of diameter D = 200 nm and height H = 250 nm, and arranged in a periodic hexagonal close-packed pattern provides a relatively low surface reflection over a broad wavelength range (300nm~1200nm) and a wide incidence angle (0°~80°).…”

“…Surface texturing such as nanorods [12], nanopillars [13], nanocones [14], nanohemisphere [15] and nanopyramids [16] have been used. Very recently, we have studied the surface antireflection properties of GaN based hemi-ellipsoid microdome structures, which could significantly reduce surface reflection over a broad wavelength range and a wide incidence angle [17]. Experimentally, we have also demonstrated the feasibility to tune the surface shape and size of the GaN microdome structures by controlling the top-down plasma dry etching conditions [18].…”

Enhancement of Electron Collection and Light Trapping of Inclined GaN and AlGaN Nanowire Arrays

“…[ 18,19 ] The light‐absorption process of NWA can also produce a strong light‐gathering effect, which has also been proven in solar cells. [ 20,21 ] The degree of light management is very sensitive to the surface shape of the nanostructure, and light capture can be improved by changing the structural parameters. For example, for Si nanowire solar cell devices, the performance of Si arrays with a certain inclined angle is better than that of vertical arrays.…”