The Impact Of Micropillar Dimensions Of An N-Zno/P-Znte Solar Cell Using Fdtd Solver

Abstract

This dissertation presents a study of three-dimensional (3D) cylindrical periodic micropillar solar cell structures made of negatively doped zinc oxide (n-ZnO) and positively doped zinc telluride (p-ZnTe). The impact of several variations in the dimensions including height, diameter/thickness and pitch of the axial and radial types of pillars has been conducted using Finite-Difference Time-Domain (FDTD) Solver in the Ansys Lumerical DEVICE Simulator software. Their analysed optical properties such as transmission, reflection and absorption indicate that the ZnO/ZnTe micropillar solar cells exhibit greater light absorption than planar ZnO/ZnTe solar cells of equal height, with a difference of roughly twelve percent (12%). They also exhibit a significant reduction in light reflection over the whole wavelength range. On the height variation, the highest degree of absorption was achieved by an absorber height of 1.0 µm (about 20%), an emitter height of 0.5 µm (also about 20%) for the axial junction micropillar; whiles the radial (core-shell) pillar height of 1.3 µm achieved more than fifty percent (50%). A pillar diameter / thickness of 240 nm leads to the highest level of absorption of about forty percent (40%) for axial diameter and about sixty percent (60%) for radial shell both within the wavelength 0.30 µm to 0.55 µm of the relevant spectrum. Whiles the radial core thickness of 140 nm attained the maximum absorption of about forty percent (40%). As for the pitch, we observe a non-monotonic response. The optimum zone has been identified at the extreme values of 0.3 µm and 0.7 µm. These findings imply that the ZnO/ZnTe combination is also promising for making solar cells with micropillars structure.