Anisotropic optical properties of silicon nanowire arrays based on the effective medium approximation

Han Wang, Xianglei Liu, Liping Wang, Zhuomin Zhang

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

In search of next-generation solar cells, silicon nanowire arrays have attracted great attention since they are cost-effective and may absorb more light compared to current thin-film silicon solar cells. Theoretical studies using finite-difference time-domain and transfer matrix methods have been performed to investigate the optical properties of silicon nanowire (SiNW) arrays. However, these methods are computationally intensive and require periodic conditions, which may not be satisfied with most fabricated samples. In the present study, an effective medium analysis considering the anisotropic nature of vertically aligned SiNWs is performed to study their optical properties in the wavelength range from 310 nm to 1100 nm, which is of the most importance for solar photovoltaic cells. The effective dielectric functions of the SiNW layer for both ordinary and extraordinary waves are obtained from the Bruggeman approximation. Thin-film optics formulae incorporating the anisotropic wave propagation in uniaxial media are employed to calculate the reflectance and absorptance of the SiNWs on silicon substrates for different polarizations. The effect of geometric parameters such as filling ratio and wire length is investigated. In addition to modeling the directional radiative properties at various angles of incidence, the hemispherical properties are also calculated to understand the light absorption and to facilitate the optimal design of high- performance SiNW solar cells.

Original languageEnglish (US)
Pages (from-to)62-69
Number of pages8
JournalInternational Journal of Thermal Sciences
Volume65
DOIs
StatePublished - Mar 2013

Fingerprint

Nanowires
nanowires
Optical properties
optical properties
Silicon
solar cells
Silicon solar cells
silicon
approximation
absorptance
Transfer matrix method
Photovoltaic cells
photovoltaic cells
thin films
electromagnetic absorption
matrix methods
Light absorption
Wave propagation
wave propagation
Optics

Keywords

  • Absorptance
  • Effective medium theory
  • Silicon nanowires
  • Thin-film optics
  • Uniaxial medium

ASJC Scopus subject areas

  • Engineering(all)
  • Condensed Matter Physics

Cite this

Anisotropic optical properties of silicon nanowire arrays based on the effective medium approximation. / Wang, Han; Liu, Xianglei; Wang, Liping; Zhang, Zhuomin.

In: International Journal of Thermal Sciences, Vol. 65, 03.2013, p. 62-69.

Research output: Contribution to journalArticle

@article{5e536b1209574cd7b15c1f51c6185c14,
title = "Anisotropic optical properties of silicon nanowire arrays based on the effective medium approximation",
abstract = "In search of next-generation solar cells, silicon nanowire arrays have attracted great attention since they are cost-effective and may absorb more light compared to current thin-film silicon solar cells. Theoretical studies using finite-difference time-domain and transfer matrix methods have been performed to investigate the optical properties of silicon nanowire (SiNW) arrays. However, these methods are computationally intensive and require periodic conditions, which may not be satisfied with most fabricated samples. In the present study, an effective medium analysis considering the anisotropic nature of vertically aligned SiNWs is performed to study their optical properties in the wavelength range from 310 nm to 1100 nm, which is of the most importance for solar photovoltaic cells. The effective dielectric functions of the SiNW layer for both ordinary and extraordinary waves are obtained from the Bruggeman approximation. Thin-film optics formulae incorporating the anisotropic wave propagation in uniaxial media are employed to calculate the reflectance and absorptance of the SiNWs on silicon substrates for different polarizations. The effect of geometric parameters such as filling ratio and wire length is investigated. In addition to modeling the directional radiative properties at various angles of incidence, the hemispherical properties are also calculated to understand the light absorption and to facilitate the optimal design of high- performance SiNW solar cells.",
keywords = "Absorptance, Effective medium theory, Silicon nanowires, Thin-film optics, Uniaxial medium",
author = "Han Wang and Xianglei Liu and Liping Wang and Zhuomin Zhang",
year = "2013",
month = "3",
doi = "10.1016/j.ijthermalsci.2012.08.018",
language = "English (US)",
volume = "65",
pages = "62--69",
journal = "International Journal of Thermal Sciences",
issn = "1290-0729",
publisher = "Elsevier Masson SAS",

}

TY - JOUR

T1 - Anisotropic optical properties of silicon nanowire arrays based on the effective medium approximation

AU - Wang, Han

AU - Liu, Xianglei

AU - Wang, Liping

AU - Zhang, Zhuomin

PY - 2013/3

Y1 - 2013/3

N2 - In search of next-generation solar cells, silicon nanowire arrays have attracted great attention since they are cost-effective and may absorb more light compared to current thin-film silicon solar cells. Theoretical studies using finite-difference time-domain and transfer matrix methods have been performed to investigate the optical properties of silicon nanowire (SiNW) arrays. However, these methods are computationally intensive and require periodic conditions, which may not be satisfied with most fabricated samples. In the present study, an effective medium analysis considering the anisotropic nature of vertically aligned SiNWs is performed to study their optical properties in the wavelength range from 310 nm to 1100 nm, which is of the most importance for solar photovoltaic cells. The effective dielectric functions of the SiNW layer for both ordinary and extraordinary waves are obtained from the Bruggeman approximation. Thin-film optics formulae incorporating the anisotropic wave propagation in uniaxial media are employed to calculate the reflectance and absorptance of the SiNWs on silicon substrates for different polarizations. The effect of geometric parameters such as filling ratio and wire length is investigated. In addition to modeling the directional radiative properties at various angles of incidence, the hemispherical properties are also calculated to understand the light absorption and to facilitate the optimal design of high- performance SiNW solar cells.

AB - In search of next-generation solar cells, silicon nanowire arrays have attracted great attention since they are cost-effective and may absorb more light compared to current thin-film silicon solar cells. Theoretical studies using finite-difference time-domain and transfer matrix methods have been performed to investigate the optical properties of silicon nanowire (SiNW) arrays. However, these methods are computationally intensive and require periodic conditions, which may not be satisfied with most fabricated samples. In the present study, an effective medium analysis considering the anisotropic nature of vertically aligned SiNWs is performed to study their optical properties in the wavelength range from 310 nm to 1100 nm, which is of the most importance for solar photovoltaic cells. The effective dielectric functions of the SiNW layer for both ordinary and extraordinary waves are obtained from the Bruggeman approximation. Thin-film optics formulae incorporating the anisotropic wave propagation in uniaxial media are employed to calculate the reflectance and absorptance of the SiNWs on silicon substrates for different polarizations. The effect of geometric parameters such as filling ratio and wire length is investigated. In addition to modeling the directional radiative properties at various angles of incidence, the hemispherical properties are also calculated to understand the light absorption and to facilitate the optimal design of high- performance SiNW solar cells.

KW - Absorptance

KW - Effective medium theory

KW - Silicon nanowires

KW - Thin-film optics

KW - Uniaxial medium

UR - http://www.scopus.com/inward/record.url?scp=84871717012&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84871717012&partnerID=8YFLogxK

U2 - 10.1016/j.ijthermalsci.2012.08.018

DO - 10.1016/j.ijthermalsci.2012.08.018

M3 - Article

AN - SCOPUS:84871717012

VL - 65

SP - 62

EP - 69

JO - International Journal of Thermal Sciences

JF - International Journal of Thermal Sciences

SN - 1290-0729

ER -