Zinc aluminate spinel impurity phase in Al doped ZnO ceramic target and pulsed laser ablated films: Curse or blessing?

Arindam Mallick; Arindam Kole; Tushar Ghosh; Partha Chaudhuri; Durga Basak

doi:10.1016/j.solener.2014.05.049

Zinc aluminate spinel impurity phase in Al doped ZnO ceramic target and pulsed laser ablated films: Curse or blessing?

Arindam Mallick, Arindam Kole, Tushar Ghosh, Partha Chaudhuri, Durga Basak

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

26 Scopus citations

Abstract

Al doped ZnO films (AZO) have been grown by pulsed laser deposition (PLD) technique using ceramic targets sintered at different temperatures in the range 800-1400°C. The effect of target sintering temperature on the structural, optical and electrical properties of the AZO films has been investigated. The X-ray diffraction (XRD) patterns show that besides the major hexagonal wurtzite phase of ZnO, the zinc aluminate (ZnAl₂O₄) spinel impurity phase is present predominantly in the targets sintered at 900°C onwards. The XRD peak intensity of the spinel phase increases as the sintering temperature increases. Although, no such impurity has been primarily appeared in the XRD pattern of the films deposited from these targets, the presence of a probable spinel phase has been sensed by the X-ray photoelectron spectroscopy (XPS) measurements. All the films show more than 90% transparency in the region 500-1400nm. The electrical resistance of the target pellets also decreases with an increase in the sintering temperature up to 1100°C and then increases. Similarly, the carrier concentration increases and the resistivity decreases with the sintering temperature attaining the values of 6.36×10²⁰cm^-3 and 6.38×10^-4Ωcm respectively for the films ablated from the targets sintered at temperatures 1000°C (AZO1000) and 1100°C (AZO1100) beyond which both the values deteriorate. An increase in the carrier concentration value is assigned to the modification of the grain boundaries by the spinel phase. Vacuum annealing of AZO1000 film at 350°C results in a further increase in the carrier concentration to a value of 1×10²¹cm^-3. This film has been applied as a transparent electrode without texturing for a-Si:H solar cell which shows a conversion efficiency of ~3.93%. Our study for the first time shows that the presence of a ZnAl₂O₄ phase to a certain extent in AZO film rather helps to achieve higher carrier concentration.

Original language	English
Pages (from-to)	80-87
Number of pages	8
Journal	Solar Energy
Volume	108
DOIs	https://doi.org/10.1016/j.solener.2014.05.049
State	Published - 1 Jan 2014
Externally published	Yes

Keywords

Al doped ZnO
Impurity phase
Pulsed laser deposition
Transparent electrode

ASJC Scopus subject areas

Renewable Energy, Sustainability and the Environment
General Materials Science

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.solener.2014.05.049

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@article{c18973c3d73846c4a9da70a42241ad84,

title = "Zinc aluminate spinel impurity phase in Al doped ZnO ceramic target and pulsed laser ablated films: Curse or blessing?",

abstract = "Al doped ZnO films (AZO) have been grown by pulsed laser deposition (PLD) technique using ceramic targets sintered at different temperatures in the range 800-1400°C. The effect of target sintering temperature on the structural, optical and electrical properties of the AZO films has been investigated. The X-ray diffraction (XRD) patterns show that besides the major hexagonal wurtzite phase of ZnO, the zinc aluminate (ZnAl2O4) spinel impurity phase is present predominantly in the targets sintered at 900°C onwards. The XRD peak intensity of the spinel phase increases as the sintering temperature increases. Although, no such impurity has been primarily appeared in the XRD pattern of the films deposited from these targets, the presence of a probable spinel phase has been sensed by the X-ray photoelectron spectroscopy (XPS) measurements. All the films show more than 90% transparency in the region 500-1400nm. The electrical resistance of the target pellets also decreases with an increase in the sintering temperature up to 1100°C and then increases. Similarly, the carrier concentration increases and the resistivity decreases with the sintering temperature attaining the values of 6.36×1020cm-3 and 6.38×10-4Ωcm respectively for the films ablated from the targets sintered at temperatures 1000°C (AZO1000) and 1100°C (AZO1100) beyond which both the values deteriorate. An increase in the carrier concentration value is assigned to the modification of the grain boundaries by the spinel phase. Vacuum annealing of AZO1000 film at 350°C results in a further increase in the carrier concentration to a value of 1×1021cm-3. This film has been applied as a transparent electrode without texturing for a-Si:H solar cell which shows a conversion efficiency of ~3.93%. Our study for the first time shows that the presence of a ZnAl2O4 phase to a certain extent in AZO film rather helps to achieve higher carrier concentration.",

keywords = "Al doped ZnO, Impurity phase, Pulsed laser deposition, Transparent electrode",

author = "Arindam Mallick and Arindam Kole and Tushar Ghosh and Partha Chaudhuri and Durga Basak",

note = "Funding Information: This (paper) is based upon work supported in part under the US–India Partnership to Advance Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the US Department of Energy ( Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program , under Subcontract DE-AC 36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India , through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012 dated 22nd November 2012. The authors would also like to thank the DST Unit of Nanoscience at IACS for the XPS and PLD instrumental supports.",

year = "2014",

month = jan,

day = "1",

doi = "10.1016/j.solener.2014.05.049",

language = "English",

volume = "108",

pages = "80--87",

journal = "Solar Energy",

issn = "0038-092X",

publisher = "Elsevier Ltd.",

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TY - JOUR

T1 - Zinc aluminate spinel impurity phase in Al doped ZnO ceramic target and pulsed laser ablated films

T2 - Curse or blessing?

AU - Mallick, Arindam

AU - Kole, Arindam

AU - Ghosh, Tushar

AU - Chaudhuri, Partha

AU - Basak, Durga

N1 - Funding Information: This (paper) is based upon work supported in part under the US–India Partnership to Advance Clean Energy-Research (PACE-R) for the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the US Department of Energy ( Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program , under Subcontract DE-AC 36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India , through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012 dated 22nd November 2012. The authors would also like to thank the DST Unit of Nanoscience at IACS for the XPS and PLD instrumental supports.

PY - 2014/1/1

Y1 - 2014/1/1

N2 - Al doped ZnO films (AZO) have been grown by pulsed laser deposition (PLD) technique using ceramic targets sintered at different temperatures in the range 800-1400°C. The effect of target sintering temperature on the structural, optical and electrical properties of the AZO films has been investigated. The X-ray diffraction (XRD) patterns show that besides the major hexagonal wurtzite phase of ZnO, the zinc aluminate (ZnAl2O4) spinel impurity phase is present predominantly in the targets sintered at 900°C onwards. The XRD peak intensity of the spinel phase increases as the sintering temperature increases. Although, no such impurity has been primarily appeared in the XRD pattern of the films deposited from these targets, the presence of a probable spinel phase has been sensed by the X-ray photoelectron spectroscopy (XPS) measurements. All the films show more than 90% transparency in the region 500-1400nm. The electrical resistance of the target pellets also decreases with an increase in the sintering temperature up to 1100°C and then increases. Similarly, the carrier concentration increases and the resistivity decreases with the sintering temperature attaining the values of 6.36×1020cm-3 and 6.38×10-4Ωcm respectively for the films ablated from the targets sintered at temperatures 1000°C (AZO1000) and 1100°C (AZO1100) beyond which both the values deteriorate. An increase in the carrier concentration value is assigned to the modification of the grain boundaries by the spinel phase. Vacuum annealing of AZO1000 film at 350°C results in a further increase in the carrier concentration to a value of 1×1021cm-3. This film has been applied as a transparent electrode without texturing for a-Si:H solar cell which shows a conversion efficiency of ~3.93%. Our study for the first time shows that the presence of a ZnAl2O4 phase to a certain extent in AZO film rather helps to achieve higher carrier concentration.

AB - Al doped ZnO films (AZO) have been grown by pulsed laser deposition (PLD) technique using ceramic targets sintered at different temperatures in the range 800-1400°C. The effect of target sintering temperature on the structural, optical and electrical properties of the AZO films has been investigated. The X-ray diffraction (XRD) patterns show that besides the major hexagonal wurtzite phase of ZnO, the zinc aluminate (ZnAl2O4) spinel impurity phase is present predominantly in the targets sintered at 900°C onwards. The XRD peak intensity of the spinel phase increases as the sintering temperature increases. Although, no such impurity has been primarily appeared in the XRD pattern of the films deposited from these targets, the presence of a probable spinel phase has been sensed by the X-ray photoelectron spectroscopy (XPS) measurements. All the films show more than 90% transparency in the region 500-1400nm. The electrical resistance of the target pellets also decreases with an increase in the sintering temperature up to 1100°C and then increases. Similarly, the carrier concentration increases and the resistivity decreases with the sintering temperature attaining the values of 6.36×1020cm-3 and 6.38×10-4Ωcm respectively for the films ablated from the targets sintered at temperatures 1000°C (AZO1000) and 1100°C (AZO1100) beyond which both the values deteriorate. An increase in the carrier concentration value is assigned to the modification of the grain boundaries by the spinel phase. Vacuum annealing of AZO1000 film at 350°C results in a further increase in the carrier concentration to a value of 1×1021cm-3. This film has been applied as a transparent electrode without texturing for a-Si:H solar cell which shows a conversion efficiency of ~3.93%. Our study for the first time shows that the presence of a ZnAl2O4 phase to a certain extent in AZO film rather helps to achieve higher carrier concentration.

KW - Al doped ZnO

KW - Impurity phase

KW - Pulsed laser deposition

KW - Transparent electrode

UR - http://www.scopus.com/inward/record.url?scp=84904629440&partnerID=8YFLogxK

U2 - 10.1016/j.solener.2014.05.049

DO - 10.1016/j.solener.2014.05.049

M3 - Article

AN - SCOPUS:84904629440

SN - 0038-092X

VL - 108

SP - 80

EP - 87

JO - Solar Energy

JF - Solar Energy

ER -

Zinc aluminate spinel impurity phase in Al doped ZnO ceramic target and pulsed laser ablated films: Curse or blessing?

Abstract

Keywords

ASJC Scopus subject areas

UN SDGs

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