Ultrafast carrier dynamics in Cu(In,Ga)Se2 thin films probed by femtosecond pump-probe spectroscopy

Shih Chen Chen; Yu Kuang Liao; Hsueh Ju Chen; Chia Hsiang Chen; Chih Huang Lai; Yu Lun Chueh; Hao-Chung Kuo; Kaung-Hsiung Wu; Jenh-Yih Juang; Shun-Jen Cheng; Tung Po Hsieh; Takayoshi Kobayashi

doi:10.1364/OE.20.012675

Ultrafast carrier dynamics in Cu(In,Ga)Se2 thin films probed by femtosecond pump-probe spectroscopy

Shih Chen Chen^*
, Yu Kuang Liao
, Hsueh Ju Chen
, Chia Hsiang Chen
, Chih Huang Lai
, Yu Lun Chueh
, Hao-Chung Kuo
, Kaung-Hsiung Wu
, Jenh-Yih Juang
, Shun-Jen Cheng
, Tung Po Hsieh
, Takayoshi Kobayashi

^*Corresponding author for this work

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

15 Scopus citations

Abstract

Ultrafast carrier dynamics in Cu(In,Ga)Se2 films are investigated using femtosecond pump-probe spectroscopy. Samples prepared by direct sputtering and co-evaporation processes, which exhibited remarkably different crystalline structures and free carrier densities, were found to result in substantially different carrier relaxation and recombination mechanisms. For the sputtered CIGS films, electron-electron scattering and Auger recombination was observed, whereas for the co-evaporated CIGS films, bandgap renormalization accompanied by band filling effect and hot phonon relaxation was observed. The lifetime of defect-related recombination in the co-evaporated CIGS films is much longer than that in the direct-sputtered CIGS films, reflecting a better quality with higher energy conversion efficiency of the former.

Original language	English
Pages (from-to)	12675-12681
Number of pages	7
Journal	Optics Express
Volume	20
Issue number	12
DOIs	https://doi.org/10.1364/OE.20.012675
State	Published - 4 Jun 2012

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title = "Ultrafast carrier dynamics in Cu(In,Ga)Se2 thin films probed by femtosecond pump-probe spectroscopy",

abstract = "Ultrafast carrier dynamics in Cu(In,Ga)Se2 films are investigated using femtosecond pump-probe spectroscopy. Samples prepared by direct sputtering and co-evaporation processes, which exhibited remarkably different crystalline structures and free carrier densities, were found to result in substantially different carrier relaxation and recombination mechanisms. For the sputtered CIGS films, electron-electron scattering and Auger recombination was observed, whereas for the co-evaporated CIGS films, bandgap renormalization accompanied by band filling effect and hot phonon relaxation was observed. The lifetime of defect-related recombination in the co-evaporated CIGS films is much longer than that in the direct-sputtered CIGS films, reflecting a better quality with higher energy conversion efficiency of the former.",

author = "Chen, \{Shih Chen\} and Liao, \{Yu Kuang\} and Chen, \{Hsueh Ju\} and Chen, \{Chia Hsiang\} and Lai, \{Chih Huang\} and Chueh, \{Yu Lun\} and Hao-Chung Kuo and Kaung-Hsiung Wu and Jenh-Yih Juang and Shun-Jen Cheng and Hsieh, \{Tung Po\} and Takayoshi Kobayashi",

year = "2012",

month = jun,

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doi = "10.1364/OE.20.012675",

language = "English",

volume = "20",

pages = "12675--12681",

journal = "Optics Express",

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TY - JOUR

T1 - Ultrafast carrier dynamics in Cu(In,Ga)Se2 thin films probed by femtosecond pump-probe spectroscopy

AU - Chen, Shih Chen

AU - Liao, Yu Kuang

AU - Chen, Hsueh Ju

AU - Chen, Chia Hsiang

AU - Lai, Chih Huang

AU - Chueh, Yu Lun

AU - Kuo, Hao-Chung

AU - Wu, Kaung-Hsiung

AU - Juang, Jenh-Yih

AU - Cheng, Shun-Jen

AU - Hsieh, Tung Po

AU - Kobayashi, Takayoshi

PY - 2012/6/4

Y1 - 2012/6/4

N2 - Ultrafast carrier dynamics in Cu(In,Ga)Se2 films are investigated using femtosecond pump-probe spectroscopy. Samples prepared by direct sputtering and co-evaporation processes, which exhibited remarkably different crystalline structures and free carrier densities, were found to result in substantially different carrier relaxation and recombination mechanisms. For the sputtered CIGS films, electron-electron scattering and Auger recombination was observed, whereas for the co-evaporated CIGS films, bandgap renormalization accompanied by band filling effect and hot phonon relaxation was observed. The lifetime of defect-related recombination in the co-evaporated CIGS films is much longer than that in the direct-sputtered CIGS films, reflecting a better quality with higher energy conversion efficiency of the former.

AB - Ultrafast carrier dynamics in Cu(In,Ga)Se2 films are investigated using femtosecond pump-probe spectroscopy. Samples prepared by direct sputtering and co-evaporation processes, which exhibited remarkably different crystalline structures and free carrier densities, were found to result in substantially different carrier relaxation and recombination mechanisms. For the sputtered CIGS films, electron-electron scattering and Auger recombination was observed, whereas for the co-evaporated CIGS films, bandgap renormalization accompanied by band filling effect and hot phonon relaxation was observed. The lifetime of defect-related recombination in the co-evaporated CIGS films is much longer than that in the direct-sputtered CIGS films, reflecting a better quality with higher energy conversion efficiency of the former.

UR - https://www.scopus.com/pages/publications/84863771441

U2 - 10.1364/OE.20.012675

DO - 10.1364/OE.20.012675

M3 - Article

C2 - 22714296

AN - SCOPUS:84863771441

SN - 1094-4087

VL - 20

SP - 12675

EP - 12681

JO - Optics Express

JF - Optics Express

IS - 12

ER -

Ultrafast carrier dynamics in Cu(In,Ga)Se2 thin films probed by femtosecond pump-probe spectroscopy

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