Strong carrier lifetime enhancement in GaAs nanowires coated with semiconducting polymer

Chaw Keong Yong; Keian Noori; Qiang Gao; Hannah J. Joyce; H. Hoe Tan; Chennupati Jagadish; Feliciano Giustino; Michael B. Johnston; Laura M. Herz

doi:10.1021/nl3034027

Strong carrier lifetime enhancement in GaAs nanowires coated with semiconducting polymer

Chaw Keong Yong, Keian Noori, Qiang Gao, Hannah J. Joyce, H. Hoe Tan, Chennupati Jagadish, Feliciano Giustino, Michael B. Johnston, Laura M. Herz^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

62 Citations (Scopus)

Abstract

The ultrafast charge carrier dynamics in GaAs/conjugated polymer type II heterojunctions are investigated using time-resolved photoluminescence spectroscopy at 10 K. By probing the photoluminescence at the band edge of GaAs, we observe strong carrier lifetime enhancement for nanowires blended with semiconducting polymers. The enhancement is found to depend crucially on the ionization potential of the polymers with respect to the Fermi energy level at the surface of the GaAs nanowires. We attribute these effects to electron doping by the polymer which reduces the unsaturated surface-state density in GaAs. We find that when the surface of nanowires is terminated by native oxide, the electron injection across the interface is greatly reduced and such surface doping is absent. Our results suggest that surface engineering via π-conjugated polymers can substantially improve the carrier lifetime in nanowire hybrid heterojunctions with applications in photovoltaics and nanoscale photodetectors.

Original language	English
Pages (from-to)	6293-6301
Number of pages	9
Journal	Nano Letters
Volume	12
Issue number	12
DOIs	https://doi.org/10.1021/nl3034027
Publication status	Published - 12 Dec 2012

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title = "Strong carrier lifetime enhancement in GaAs nanowires coated with semiconducting polymer",

abstract = "The ultrafast charge carrier dynamics in GaAs/conjugated polymer type II heterojunctions are investigated using time-resolved photoluminescence spectroscopy at 10 K. By probing the photoluminescence at the band edge of GaAs, we observe strong carrier lifetime enhancement for nanowires blended with semiconducting polymers. The enhancement is found to depend crucially on the ionization potential of the polymers with respect to the Fermi energy level at the surface of the GaAs nanowires. We attribute these effects to electron doping by the polymer which reduces the unsaturated surface-state density in GaAs. We find that when the surface of nanowires is terminated by native oxide, the electron injection across the interface is greatly reduced and such surface doping is absent. Our results suggest that surface engineering via π-conjugated polymers can substantially improve the carrier lifetime in nanowire hybrid heterojunctions with applications in photovoltaics and nanoscale photodetectors.",

keywords = "GaAs, Nanowires, charge trapping, hybrid photovoltaics, organic semiconductors, ultrafast spectroscopy",

author = "Yong, {Chaw Keong} and Keian Noori and Qiang Gao and Joyce, {Hannah J.} and Tan, {H. Hoe} and Chennupati Jagadish and Feliciano Giustino and Johnston, {Michael B.} and Herz, {Laura M.}",

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T1 - Strong carrier lifetime enhancement in GaAs nanowires coated with semiconducting polymer

AU - Yong, Chaw Keong

AU - Noori, Keian

AU - Gao, Qiang

AU - Joyce, Hannah J.

AU - Tan, H. Hoe

AU - Jagadish, Chennupati

AU - Giustino, Feliciano

AU - Johnston, Michael B.

AU - Herz, Laura M.

PY - 2012/12/12

Y1 - 2012/12/12

N2 - The ultrafast charge carrier dynamics in GaAs/conjugated polymer type II heterojunctions are investigated using time-resolved photoluminescence spectroscopy at 10 K. By probing the photoluminescence at the band edge of GaAs, we observe strong carrier lifetime enhancement for nanowires blended with semiconducting polymers. The enhancement is found to depend crucially on the ionization potential of the polymers with respect to the Fermi energy level at the surface of the GaAs nanowires. We attribute these effects to electron doping by the polymer which reduces the unsaturated surface-state density in GaAs. We find that when the surface of nanowires is terminated by native oxide, the electron injection across the interface is greatly reduced and such surface doping is absent. Our results suggest that surface engineering via π-conjugated polymers can substantially improve the carrier lifetime in nanowire hybrid heterojunctions with applications in photovoltaics and nanoscale photodetectors.

AB - The ultrafast charge carrier dynamics in GaAs/conjugated polymer type II heterojunctions are investigated using time-resolved photoluminescence spectroscopy at 10 K. By probing the photoluminescence at the band edge of GaAs, we observe strong carrier lifetime enhancement for nanowires blended with semiconducting polymers. The enhancement is found to depend crucially on the ionization potential of the polymers with respect to the Fermi energy level at the surface of the GaAs nanowires. We attribute these effects to electron doping by the polymer which reduces the unsaturated surface-state density in GaAs. We find that when the surface of nanowires is terminated by native oxide, the electron injection across the interface is greatly reduced and such surface doping is absent. Our results suggest that surface engineering via π-conjugated polymers can substantially improve the carrier lifetime in nanowire hybrid heterojunctions with applications in photovoltaics and nanoscale photodetectors.

KW - GaAs

KW - Nanowires

KW - charge trapping

KW - hybrid photovoltaics

KW - organic semiconductors

KW - ultrafast spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=84870900457&partnerID=8YFLogxK

U2 - 10.1021/nl3034027

DO - 10.1021/nl3034027

M3 - Article

SN - 1530-6984

VL - 12

SP - 6293

EP - 6301

JO - Nano Letters

JF - Nano Letters

IS - 12

ER -

Strong carrier lifetime enhancement in GaAs nanowires coated with semiconducting polymer

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