Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference

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Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference. / Anttu, Nicklas; Namazi, Kousar; Wu, Phillip; Yang, Pengfei; Xu, Hongxing; Xu, Hongqi; Håkanson, Ulf.

I: Nano Reseach, Vol. 5, Nr. 12, 2012, s. 863-874.

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Anttu, Nicklas ; Namazi, Kousar ; Wu, Phillip ; Yang, Pengfei ; Xu, Hongxing ; Xu, Hongqi ; Håkanson, Ulf. / Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference. I: Nano Reseach. 2012 ; Vol. 5, Nr. 12. s. 863-874.

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TY - JOUR

T1 - Drastically increased absorption in vertical semiconductor nanowire arrays: A non-absorbing dielectric shell makes the difference

AU - Anttu, Nicklas

AU - Namazi, Kousar

AU - Wu, Phillip

AU - Yang, Pengfei

AU - Xu, Hongxing

AU - Xu, Hongqi

AU - Håkanson, Ulf

PY - 2012

Y1 - 2012

N2 - Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into the absorbing NW core with increasing thickness of the dielectric shell until a resonant shell thickness is reached. We provide a simple description of how to reach this strongly absorbing resonance condition, making our results easy to apply for a broad wavelength range and a multifold of semiconductor and dielectric coating material combinations.

AB - Enhanced absorption of especially long wavelength light is needed to enable the full potential of semiconductor nanowire (NW) arrays for optoelectronic applications. We show both experimentally and theoretically that a transparent dielectric shell (Al2O3 coating) can drastically improve the absorption of light in InAs NW arrays. With an appropriate thickness of the Al2O3 shell, we achieve four times stronger absorption in the NWs compared to uncoated NWs and twice as good absorption as when the dielectric completely fills the space between the NWs. We provide detailed theoretical analysis from a combination of full electrodynamic modeling and intuitive electrostatic approximations. This reveals how the incident light penetrates better into the absorbing NW core with increasing thickness of the dielectric shell until a resonant shell thickness is reached. We provide a simple description of how to reach this strongly absorbing resonance condition, making our results easy to apply for a broad wavelength range and a multifold of semiconductor and dielectric coating material combinations.

KW - Nanowire array

KW - InAs

KW - absorption

KW - photovoltaics

KW - core-shell

KW - Al2O3

KW - coating

U2 - 10.1007/s12274-012-0270-x

DO - 10.1007/s12274-012-0270-x

M3 - Article

VL - 5

SP - 863

EP - 874

JO - Nano Reseach

T2 - Nano Reseach

JF - Nano Reseach

SN - 1998-0124

IS - 12

ER -