ZnO-based semiconductors with tunable band gap for solar sell applications

Naho Itagaki; K. Matsushima; D. Yamashita; Hyunwoong Seo; Kazunori Koga; Masaharu Shiratani

doi:10.1117/12.2078114

ZnO-based semiconductors with tunable band gap for solar sell applications

Naho Itagaki, K. Matsushima, D. Yamashita, Hyunwoong Seo, Kazunori Koga, Masaharu Shiratani

Electronic Devices

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

In this study, we discuss the potential advantages of a new ZnO-based semiconductor, ZnInON (ZION), for application in multi quantum-well (MQW) photovoltaics. ZION is a pseudo-binary alloy of ZnO and InN, which has direct and tunable band gaps over the entire visible spectrum. It was found from simulation results that owing to the large piezoelectric constant, the spatial overlap of the electron and hole wave functions in the QWs is significantly small on the order of 10^-2, where the strong piezoelectric field enhances the separation of photo generated carriers. As a result, ZION QWs have low carrier recombination rate of 10¹⁴-10¹⁸ cm^-3s^-1, which is much lower than that in conventional QWs such as InGaAs/GaAs QW (10¹⁹ cm^-3s^-1) and InGaN/GaN QW (10¹⁸-10¹⁸ cm^-3s^-1). The long carrier life time in ZION QWs (ə1/41μs) should enable the extraction of photo-generated carriers from well layers before the recombination, and thus increase V_oc and J_sc. These simulation results are consistent with our experimental data showing that both V_oc and J_sc of a p-i-n solar cell with strained ZION MQWs and thus the efficiency were increased by the superimposition of laser light with lower photon energy than the band gap energy of the QWs. Since the laser light contributed not to carrier generation but to the carrier extraction from the QWs, and no increase in V_oc and J_sc was observed for relaxed ZION MQWs, the improvement in the efficiency was attributed to the long carrier lifetime in the strained ZION QWs.

Original language	English
Title of host publication	Oxide-Based Materials and Devices VI
Editors	Ferechteh H. Teherani, David C. Look, David J. Rogers
Publisher	SPIE
Volume	9364
ISBN (Electronic)	9781628414547
DOIs	https://doi.org/10.1117/12.2078114
Publication status	Published - Jan 1 2015
Event	Oxide-Based Materials and Devices VI - San Francisco, United States Duration: Feb 8 2015 → Feb 11 2015

Other

Other	Oxide-Based Materials and Devices VI
Country	United States
City	San Francisco
Period	2/8/15 → 2/11/15

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Computer Science Applications
Applied Mathematics
Electrical and Electronic Engineering

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ZnO-based semiconductors with tunable band gap for solar sell applications. / Itagaki, Naho; Matsushima, K.; Yamashita, D.; Seo, Hyunwoong; Koga, Kazunori ; Shiratani, Masaharu.

Oxide-Based Materials and Devices VI. ed. / Ferechteh H. Teherani; David C. Look; David J. Rogers. Vol. 9364 SPIE, 2015. 93640P.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Itagaki, N, Matsushima, K, Yamashita, D, Seo, H, Koga, K & Shiratani, M 2015, ZnO-based semiconductors with tunable band gap for solar sell applications. in FH Teherani, DC Look & DJ Rogers (eds), Oxide-Based Materials and Devices VI. vol. 9364, 93640P, SPIE, Oxide-Based Materials and Devices VI, San Francisco, United States, 2/8/15. https://doi.org/10.1117/12.2078114

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abstract = "In this study, we discuss the potential advantages of a new ZnO-based semiconductor, ZnInON (ZION), for application in multi quantum-well (MQW) photovoltaics. ZION is a pseudo-binary alloy of ZnO and InN, which has direct and tunable band gaps over the entire visible spectrum. It was found from simulation results that owing to the large piezoelectric constant, the spatial overlap of the electron and hole wave functions in the QWs is significantly small on the order of 10-2, where the strong piezoelectric field enhances the separation of photo generated carriers. As a result, ZION QWs have low carrier recombination rate of 1014-1018 cm-3s-1, which is much lower than that in conventional QWs such as InGaAs/GaAs QW (1019 cm-3s-1) and InGaN/GaN QW (1018-1018 cm-3s-1). The long carrier life time in ZION QWs (ə1/41μs) should enable the extraction of photo-generated carriers from well layers before the recombination, and thus increase Voc and Jsc. These simulation results are consistent with our experimental data showing that both Voc and Jsc of a p-i-n solar cell with strained ZION MQWs and thus the efficiency were increased by the superimposition of laser light with lower photon energy than the band gap energy of the QWs. Since the laser light contributed not to carrier generation but to the carrier extraction from the QWs, and no increase in Voc and Jsc was observed for relaxed ZION MQWs, the improvement in the efficiency was attributed to the long carrier lifetime in the strained ZION QWs.",

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AU - Itagaki, Naho

AU - Matsushima, K.

AU - Yamashita, D.

AU - Seo, Hyunwoong

AU - Koga, Kazunori

AU - Shiratani, Masaharu

PY - 2015/1/1

Y1 - 2015/1/1

N2 - In this study, we discuss the potential advantages of a new ZnO-based semiconductor, ZnInON (ZION), for application in multi quantum-well (MQW) photovoltaics. ZION is a pseudo-binary alloy of ZnO and InN, which has direct and tunable band gaps over the entire visible spectrum. It was found from simulation results that owing to the large piezoelectric constant, the spatial overlap of the electron and hole wave functions in the QWs is significantly small on the order of 10-2, where the strong piezoelectric field enhances the separation of photo generated carriers. As a result, ZION QWs have low carrier recombination rate of 1014-1018 cm-3s-1, which is much lower than that in conventional QWs such as InGaAs/GaAs QW (1019 cm-3s-1) and InGaN/GaN QW (1018-1018 cm-3s-1). The long carrier life time in ZION QWs (ə1/41μs) should enable the extraction of photo-generated carriers from well layers before the recombination, and thus increase Voc and Jsc. These simulation results are consistent with our experimental data showing that both Voc and Jsc of a p-i-n solar cell with strained ZION MQWs and thus the efficiency were increased by the superimposition of laser light with lower photon energy than the band gap energy of the QWs. Since the laser light contributed not to carrier generation but to the carrier extraction from the QWs, and no increase in Voc and Jsc was observed for relaxed ZION MQWs, the improvement in the efficiency was attributed to the long carrier lifetime in the strained ZION QWs.

AB - In this study, we discuss the potential advantages of a new ZnO-based semiconductor, ZnInON (ZION), for application in multi quantum-well (MQW) photovoltaics. ZION is a pseudo-binary alloy of ZnO and InN, which has direct and tunable band gaps over the entire visible spectrum. It was found from simulation results that owing to the large piezoelectric constant, the spatial overlap of the electron and hole wave functions in the QWs is significantly small on the order of 10-2, where the strong piezoelectric field enhances the separation of photo generated carriers. As a result, ZION QWs have low carrier recombination rate of 1014-1018 cm-3s-1, which is much lower than that in conventional QWs such as InGaAs/GaAs QW (1019 cm-3s-1) and InGaN/GaN QW (1018-1018 cm-3s-1). The long carrier life time in ZION QWs (ə1/41μs) should enable the extraction of photo-generated carriers from well layers before the recombination, and thus increase Voc and Jsc. These simulation results are consistent with our experimental data showing that both Voc and Jsc of a p-i-n solar cell with strained ZION MQWs and thus the efficiency were increased by the superimposition of laser light with lower photon energy than the band gap energy of the QWs. Since the laser light contributed not to carrier generation but to the carrier extraction from the QWs, and no increase in Voc and Jsc was observed for relaxed ZION MQWs, the improvement in the efficiency was attributed to the long carrier lifetime in the strained ZION QWs.

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BT - Oxide-Based Materials and Devices VI

A2 - Teherani, Ferechteh H.

A2 - Look, David C.

A2 - Rogers, David J.

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Y2 - 8 February 2015 through 11 February 2015

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