Comparison of absorption simulation in semiconductor nanowire and nanocone arrays with the Fourier modal method, the finite element method, and the finite-difference time-domain method

Nicklas Anttu,Antti Matikainen,Henrik Mäntynen,Harri Lipsanen,Toufik Sadi,Jari Turunen

doi:10.1088/2632-959x/abd0d6

Nicklas Anttu, Antti Matikainen + Show 4 more

Open Access

https://doi.org/10.1088/2632-959x/abd0d6

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Abstract

For the design of nanostructured semiconductor solar cells and photodetectors, optics modelling can be a useful tool that reduces the need of time-consuming and costly prototyping. We compare the performance of three of the most popular numerical simulation methods for nanostructure arrays: the Fourier modal method (FMM), the finite element method (FEM) and the finite-difference time-domain (FDTD) method. The difference between the methods in computational time can be three orders of magnitude or more for a given system. The preferential method depends on the geometry of the nanostructures, the accuracy needed from the simulations, whether we are interested in the total, volume-integrated absorption or spatially resolved absorption, and whether we are interested in broadband or narrowband response. Based on our benchmarking results, we provide guidance on how to choose the method.

Highlights

Nanostructures enable new functionality for photodetectors and solar cells by inducing, for example, light trapping to increase the absorption of incident light [1,2,3]
We show that the difference between two simulation methods can exceed a factor of 1000 in terms of computational time for a given system, depending on the geometry of the nanostructure, the accuracy needed from the simulation process, whether we are interested in the total, volume-integrated absorption or spatially resolved absorption, and whether we are interested in broadband or narrowband response
Fourier modal method (FMM) appears as the method of choice for 10−2 convergence, finite-difference timedomain (FDTD) or finite element method (FEM) for 10−3 convergence, and FEM for 10−4 convergence

Summary

Introduction

Nanostructures enable new functionality for photodetectors and solar cells by inducing, for example, light trapping to increase the absorption of incident light [1,2,3]. The optical response of such nanostructures can be complicated and strongly dependent on the geometry of the design [4,5,6,7]. We focus on nanostructure arrays in which we aim to absorb the incident light [1,2,3]. In our case of interest, the nanostructure array is not just an antireflection coating [8], but contains the photodetector or solar cell region [1,2,3]

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