Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

Ali, Haider; Yang, Xinbo; Weber, Klaus; Schoenfeld, Winston V.; Davis, Kristopher O.

doi:10.1017/s1431927617012417

Cited by 22 publications

(23 citation statements)

References 20 publications

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“…In Table , the IV parameters for the best ATOM contact cells fabricated in this work are compared with previously reported results . Especially, Ali et al tested a‐Si:H/TiO x /Al contact in a boron diffused junction solar cell because of good contact passivation of a‐Si:H/TiO x with respect to SiO x /TiO x . However, the cell performance was likely limited by a high contact resistivity and high anneal temperature of 350°C.…”

Section: Solar Cellsmentioning

confidence: 76%

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal

Cho

Melskens

Debucquoy

et al. 2018

Progress in Photovoltaics

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In this work, the ATOM (intrinsic a-Si:H/TiO x /low work function metal) structure is investigated to realize high-performance passivating electron-selective contacts for crystalline silicon solar cells. The absence of a highly doped Si region in this contact structure is meant to reduce the optoelectrical losses. We show that a low contact resistivity (ρ c ) can be obtained by the combined effect of a low work function metal, such as calcium (Φ 2.9 eV), and Fermi-level depinning in the metal-insulator-semiconductor contact structure (where in our case TiO x acts as the insulator on the intrinsic a-Si:H passivating layer). TiO x grown by ALD is effective to achieve not only a low ρ c but also good passivation properties. As an electron contact in silicon heterojunction solar cells, inserting interfacial TiO x at the i-a-Si:H/Ca interface significantly enhances the solar cell conversion efficiency. Consequently, the champion solar cell with the ATOM contact achieves a V OC of 711 mV, FF of 72.9%, J SC of 35.1 mA/cm 2 , and an efficiency of 18.2%. The achievement of a high V OC and reasonable FF without the need for a highly doped Si layer serves as a valuable proof of concept for future developments on passivating electron-selective contacts using this structure.

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Section: Solar Cellsmentioning

confidence: 76%

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal

Cho

Melskens

Debucquoy

et al. 2018

Progress in Photovoltaics

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“…In such cases, a‐Si:H( n ) and a‐Si:H( p ) act as electron‐selective and hole‐selective contacts respectively. The role of a‐Si:H( i ) is to act as buffer layer apart from passivating the Si surface whereas SiO 2 solely acts as a passivation layer …”

Section: Introductionmentioning

confidence: 99%

In Situ Transmission Electron Microscopy Study of Molybdenum Oxide Contacts for Silicon Solar Cells

Ali

Koul

Gregory

et al. 2019

Physica Status Solidi (a)

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In this study, a molybdenum oxide (MoO x ) and aluminum (Al) contact structure for crystalline silicon (c-Si) solar cells is investigated using a combination of transmission line measurements (TLM) and in-situ transmission electron microscopy (TEM). Cross-sectional high-resolution TEM (HRTEM) micrographs reveal a %2 nm silicon oxide (SiO x ) interlayer at c-Si/ MoO x interface in the as-deposited state, indicating that formation of SiO x occurs during deposition of MoO x . Moreover, oxygen diffusion takes place from MoO x toward Al resulting in the formation of a %2-3 nm aluminum oxide (AlO x ) interlayer at the MoO x /Al interface. Overall, it is observed that MoO x /Al contact is relatively stable upon annealing up to 200 C and still retains ohmic transport with sufficiently low contact resistivity.

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“…In principle, CSCs with lower contact resistivity ( ρ c ) are also prerequisites for higher PCE solar cells as well as higher passivation performance. Attempts to decrease the ρ c of ALD‐TiO x layers have been made by increasing the oxygen vacancies in the ALD‐TiO x layer during post‐annealing and using a calcium electrode with a lower work function …”

Section: Introductionmentioning

confidence: 99%

Tuning the Electrical Properties of Titanium Oxide Bilayers Prepared by Atomic Layer Deposition at Different Temperatures

Gotoh

Mochizuki

Kurokawa

et al. 2019

Physica Status Solidi (a)

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Carrier-selective contacts prepared by atomic layer deposition (ALD) have received significant attention for developing high-efficiency solar cells. Herein, the electrical properties of titanium oxide (TiO x ) prepared by ALD are manipulated by modulating the deposition temperature during ALD. Tunable electrical properties are possible due to the existence of oxygen vacancies in TiO x prepared at low deposition temperatures. TiO x layers prepared at 100 and 150 C provide a low contact resistivity and high passivation performance, respectively. A high carrier selectivity of 13.5 is achieved by stacking the TiO x layers prepared at 100 and 150 C, compared with a single TiO x layer. Modulating the deposition temperature can, therefore, improve the electrical properties of ALD-TiO x . This approach can be used to optimize the functionality of ALD-based materials.

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Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

Cited by 22 publications

References 20 publications

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal

In Situ Transmission Electron Microscopy Study of Molybdenum Oxide Contacts for Silicon Solar Cells

Tuning the Electrical Properties of Titanium Oxide Bilayers Prepared by Atomic Layer Deposition at Different Temperatures

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Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

Cited by 22 publications

References 20 publications

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiOx stack and a low work function metal

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiOx stack and a low work function metal

In Situ Transmission Electron Microscopy Study of Molybdenum Oxide Contacts for Silicon Solar Cells

Tuning the Electrical Properties of Titanium Oxide Bilayers Prepared by Atomic Layer Deposition at Different Temperatures

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Product

Resources

About

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal

Passivating electron‐selective contacts for silicon solar cells based on an a‐Si:H/TiO_x stack and a low work function metal