Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study

Ali, Haider; Koul, Supriya; Gregory, Geoffrey; Bullock, James; Javey, Ali; Kushima, Akihiro; Davis, Kristopher O.

doi:10.1038/s41598-018-31053-w

Title: Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study

Abstract

In this study, the thermal stability of a contact structure featuring hole-selective tungsten oxide (WO_x) and aluminum deposited onto p-type crystalline silicon (c-Si/WO_x/Al) was investigated using a combination of transmission line measurements (TLM) and in situ transmission electron microscopy (TEM) studies. The TEM images provide insight into why the charge carrier transport and recombination characteristics change as a function of temperature, particularly as the samples are annealed at temperatures above 500 °C. In the as-deposited state, a ≈ 2 nm silicon oxide (SiO_x) interlayer forms at the c-Si/WO_x interface and a ≈ 2–3 nm aluminum oxide (AlO_x) interlayer at the WO_x/Al interface. When annealing above 500 °C, Al diffusion begins, and above 600 °C complete intermixing of the SiO_x, WO_x, AlO_x and Al layers occurs. This results in a large drop in the contact resistivity, but is the likely reason surface recombination increases at these high temperatures, since a c-Si/Al contact is basically being formed. This work provides some fundamental insight that can help in the development of WOx films as hole-selective rear contacts for p-type solar cells. Furthermore, this study demonstrates that in situ TEM can provide valuable information about thermal stability of transition metal oxides functioning as carrier-selectivemore » contacts in silicon solar cells.« less

Authors:

Ali, Haider; Koul, Supriya;

;

; Javey, Ali; Kushima, Akihiro;

Publication Date:: Thu Aug 23 00:00:00 EDT 2018

Research Org.:: Univ. of Central Florida, Orlando, FL (United States); Univ. of California, Oakland, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office

OSTI Identifier:: 1464976

Alternate Identifier(s):: OSTI ID: 1546082; OSTI ID: 1638981

Grant/Contract Number:: EE0007533; AC02- 05CH11231; AC02-05CH11231

Resource Type:: Published Article

Journal Name:: Scientific Reports

Additional Journal Information:: Journal Name: Scientific Reports Journal Volume: 8 Journal Issue: 1; Journal ID: ISSN 2045-2322

Publisher:: Nature Publishing Group

Country of Publication:: United Kingdom

Language:: English

Subject:: 36 MATERIALS SCIENCE

Citation Formats


                    Ali, Haider, Koul, Supriya, Gregory, Geoffrey, Bullock, James, Javey, Ali, Kushima, Akihiro, and Davis, Kristopher O. Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study.  United Kingdom: N. p., 2018. 
Web.  doi:10.1038/s41598-018-31053-w.

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                    Ali, Haider, Koul, Supriya, Gregory, Geoffrey, Bullock, James, Javey, Ali, Kushima, Akihiro, & Davis, Kristopher O. Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study.  United Kingdom.  https://doi.org/10.1038/s41598-018-31053-w

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                    Ali, Haider, Koul, Supriya, Gregory, Geoffrey, Bullock, James, Javey, Ali, Kushima, Akihiro, and Davis, Kristopher O. Thu .  
"Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study".  United Kingdom.  https://doi.org/10.1038/s41598-018-31053-w.

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@article{osti_1464976,

  title        = {Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study},

  author       = {Ali, Haider and Koul, Supriya and Gregory, Geoffrey and Bullock, James and Javey, Ali and Kushima, Akihiro and Davis, Kristopher O.},

  abstractNote = {In this study, the thermal stability of a contact structure featuring hole-selective tungsten oxide (WOx) and aluminum deposited onto p-type crystalline silicon (c-Si/WOx/Al) was investigated using a combination of transmission line measurements (TLM) and in situ transmission electron microscopy (TEM) studies. The TEM images provide insight into why the charge carrier transport and recombination characteristics change as a function of temperature, particularly as the samples are annealed at temperatures above 500 °C. In the as-deposited state, a ≈ 2 nm silicon oxide (SiOx) interlayer forms at the c-Si/WOx interface and a ≈ 2–3 nm aluminum oxide (AlOx) interlayer at the WOx/Al interface. When annealing above 500 °C, Al diffusion begins, and above 600 °C complete intermixing of the SiOx, WOx, AlOx and Al layers occurs. This results in a large drop in the contact resistivity, but is the likely reason surface recombination increases at these high temperatures, since a c-Si/Al contact is basically being formed. This work provides some fundamental insight that can help in the development of WOx films as hole-selective rear contacts for p-type solar cells. Furthermore, this study demonstrates that in situ TEM can provide valuable information about thermal stability of transition metal oxides functioning as carrier-selective contacts in silicon solar cells.},

  doi          = {10.1038/s41598-018-31053-w},

  journal      = {Scientific Reports},

  number       = 1,

  volume       = 8,

  place        = {United Kingdom},

  year         = {Thu Aug 23 00:00:00 EDT 2018},

  month        = {Thu Aug 23 00:00:00 EDT 2018}

}

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Works referenced in this record:

Characterisation of thermal annealed WO _x on p-type silicon for hole-selective contacts
journal, July 2017

Lee, Chang-Yeh; Aziz, Mohammad Izzat Abdul; Wenham, Stuart
Japanese Journal of Applied Physics, Vol. 56, Issue 8S2
DOI: 10.7567/JJAP.56.08MA08

22.5% efficient silicon heterojunction solar cell with molybdenum oxide hole collector
journal, August 2015

Geissbühler, Jonas; Werner, Jérémie; Martin de Nicolas, Silvia
Applied Physics Letters, Vol. 107, Issue 8
DOI: 10.1063/1.4928747

Measurement of low resistive ohmic contacts on semiconductors
journal, January 1986

Woelk, E. G.; Krautle, H.; Beneking, H.
IEEE Transactions on Electron Devices, Vol. 33, Issue 1
DOI: 10.1109/T-ED.1986.22430

Silicon heterojunction solar cells with electron selective TiOx contact
journal, June 2016

Yang, Xinbo; Zheng, Peiting; Bi, Qunyu
Solar Energy Materials and Solar Cells, Vol. 150
DOI: 10.1016/j.solmat.2016.01.020

A Low Resistance Calcium/Reduced Titania Passivated Contact for High Efficiency Crystalline Silicon Solar Cells
journal, February 2017

Allen, Thomas G.; Bullock, James; Jeangros, Quentin
Advanced Energy Materials, Vol. 7, Issue 12
DOI: 10.1002/aenm.201602606

ITO/MoOx/a-Si:H(i) Hole-Selective Contacts for Silicon Heterojunction Solar Cells: Degradation Mechanisms and Cell Integration
journal, November 2017

Sacchetto, Davide; Jeangros, Quentin; Christmann, Gabriel
IEEE Journal of Photovoltaics, Vol. 7, Issue 6
DOI: 10.1109/JPHOTOV.2017.2756066

Selectivity issues of MoOx based hole contacts
journal, September 2017

Neusel, Lisa; Bivour, Martin; Hermle, Martin
Energy Procedia, Vol. 124
DOI: 10.1016/j.egypro.2017.09.268

Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells
journal, August 2017

Ali, Haider; Yang, Xinbo; Weber, Klaus
Microscopy and Microanalysis, Vol. 23, Issue 5
DOI: 10.1017/S1431927617012417

Improving the a-Si:H(p) rear emitter contact of n-type silicon solar cells
journal, November 2012

Bivour, Martin; Reichel, Christian; Hermle, Martin
Solar Energy Materials and Solar Cells, Vol. 106
DOI: 10.1016/j.solmat.2012.06.036

Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells
journal, December 2016

Gerling, Luis G.; Voz, Cristobal; Alcubilla, Ramón
Journal of Materials Research, Vol. 32, Issue 2
DOI: 10.1557/jmr.2016.453

Surface passivation of crystalline silicon solar cells: a review
journal, January 2000

Aberle, Armin G.
Progress in Photovoltaics: Research and Applications, Vol. 8, Issue 5, p. 473-487
DOI: 10.1002/1099-159X(200009/10)8:5<473::AID-PIP337>3.0.CO;2-D

Amorphous silicon passivated contacts for diffused junction silicon solar cells
journal, April 2014

Bullock, J.; Yan, D.; Wan, Y.
Journal of Applied Physics, Vol. 115, Issue 16
DOI: 10.1063/1.4872262

Simple silicon solar cells featuring an a-Si:H enhanced rear MIS contact
journal, July 2015

Bullock, James; Cuevas, Andres; Samundsett, Christian
Solar Energy Materials and Solar Cells, Vol. 138
DOI: 10.1016/j.solmat.2015.02.030

Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials: Transmission electron microscopy based interface analysis
journal, June 2017

Ali, Haider; Moldovan, Anamaria; Mack, Sebastian
physica status solidi (a), Vol. 214, Issue 10
DOI: 10.1002/pssa.201700286

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells
journal, February 2016

Gerling, Luis G.; Mahato, Somnath; Morales-Vilches, Anna
Solar Energy Materials and Solar Cells, Vol. 145
DOI: 10.1016/j.solmat.2015.08.028

High-Performance TiO ₂ -Based Electron-Selective Contacts for Crystalline Silicon Solar Cells
journal, May 2016

Yang, Xinbo; Bi, Qunyu; Ali, Haider
Advanced Materials, Vol. 28, Issue 28
DOI: 10.1002/adma.201600926

Oxygen vacancies in tungsten oxide and their influence on tungsten oxide/silicon heterojunction solar cells
journal, December 2016

Mews, Mathias; Korte, Lars; Rech, Bernd
Solar Energy Materials and Solar Cells, Vol. 158
DOI: 10.1016/j.solmat.2016.05.042

Influence of surface preparation and cleaning on the passivation of boron diffused silicon surfaces for high efficiency photovoltaics
journal, August 2017

Ali, Haider; Moldovan, Anamaria; Mack, Sebastian
Thin Solid Films, Vol. 636
DOI: 10.1016/j.tsf.2017.06.043

Silicon heterojunction solar cell with passivated hole selective MoO _x contact
journal, March 2014

Battaglia, Corsin; de Nicolás, Silvia Martín; De Wolf, Stefaan
Applied Physics Letters, Vol. 104, Issue 11
DOI: 10.1063/1.4868880

Molybdenum oxide MoO _x : A versatile hole contact for silicon solar cells
journal, December 2014

Bullock, James; Cuevas, Andres; Allen, Thomas
Applied Physics Letters, Vol. 105, Issue 23
DOI: 10.1063/1.4903467

Molybdenum and tungsten oxide: High work function wide band gap contact materials for hole selective contacts of silicon solar cells
journal, November 2015

Bivour, Martin; Temmler, Jan; Steinkemper, Heiko
Solar Energy Materials and Solar Cells, Vol. 142
DOI: 10.1016/j.solmat.2015.05.031

Carrier-selective contacts for Si solar cells
journal, May 2014

Feldmann, F.; Simon, M.; Bivour, M.
Applied Physics Letters, Vol. 104, Issue 18
DOI: 10.1063/1.4875904

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Title: Thermal Stability of Hole-Selective Tungsten Oxide: In Situ Transmission Electron Microscopy Study

Abstract

Citation Formats

Characterisation of thermal annealed WO x on p-type silicon for hole-selective contacts journal, July 2017

22.5% efficient silicon heterojunction solar cell with molybdenum oxide hole collector journal, August 2015

Measurement of low resistive ohmic contacts on semiconductors journal, January 1986

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ITO/MoOx/a-Si:H(i) Hole-Selective Contacts for Silicon Heterojunction Solar Cells: Degradation Mechanisms and Cell Integration journal, November 2017

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Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells journal, August 2017

Improving the a-Si:H(p) rear emitter contact of n-type silicon solar cells journal, November 2012

Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells journal, December 2016

Surface passivation of crystalline silicon solar cells: a review journal, January 2000

Amorphous silicon passivated contacts for diffused junction silicon solar cells journal, April 2014

Simple silicon solar cells featuring an a-Si:H enhanced rear MIS contact journal, July 2015

Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials: Transmission electron microscopy based interface analysis journal, June 2017

Transition metal oxides as hole-selective contacts in silicon heterojunctions solar cells journal, February 2016

High-Performance TiO 2 -Based Electron-Selective Contacts for Crystalline Silicon Solar Cells journal, May 2016

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Influence of surface preparation and cleaning on the passivation of boron diffused silicon surfaces for high efficiency photovoltaics journal, August 2017

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Amorphous silicon passivated contacts for diffused junction silicon solar cells
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