This content will become publicly available on August 25, 2023
- Award ID(s):
- 2023752
- Publication Date:
- NSF-PAR ID:
- 10354311
- Journal Name:
- Frontiers in Materials
- Volume:
- 9
- ISSN:
- 2296-8016
- Sponsoring Org:
- National Science Foundation
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Abstract Hf 0.5 Zr 0.5 O 2 (HZO) thin films are promising candidates for non-volatile memory and other related applications due to their demonstrated ferroelectricity at the nanoscale and compatibility with Si processing. However, one reason that HZO has not been fully scaled into industrial applications is due to its deleterious wake-up and fatigue behavior which leads to an inconsistent remanent polarization during cycling. In this study, we explore an interfacial engineering strategy in which we insert 1 nm Al 2 O 3 interlayers at either the top or bottom HZO/TiN interface of sequentially deposited metal-ferroelectric-metal capacitors. By inserting an interfacial layer while limiting exposure to the ambient environment, we successfully introduce a protective passivating layer of Al 2 O 3 that provides excess oxygen to mitigate vacancy formation at the interface. We report that TiN/HZO/TiN capacitors with a 1 nm Al 2 O 3 at the top interface demonstrate a higher remanent polarization (2P r ∼ 42 μ C cm −2 ) and endurance limit beyond 10 8 cycles at a cycling field amplitude of 3.5 MV cm −1 . We use time-of-flight secondary ion mass spectrometry, energy dispersive spectroscopy, and grazing incidence x-ray diffraction to elucidate the originmore »
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Rapid advancements within photovoltaics realm necessitates swift fabrication of the modules using cheap materials through cost effective manufacturing processes to achieve short cost payback time. Photovoltaics manufacturing includes chemical processing of the materials followed by thermal annealing. Yet, long-term annealing of the materials using high temperature furnaces have remained the prevalent post-processing approach in industry which necessitates alternative methods to achieve high performance modules through rapid and economical processes. Intense pulse light (IPL) has been successfully applied as a promising rapid post-process annealing for various thin film photovoltaics, particularly to process the organic-inorganic perovskite solar cell (PSC) layers. In this paper, several results pertinent to the application of IPL on perovskite and SnO2 electron transport thin films are presented and the role of IPL on rapid thermal annealing (RTA) is explained. We show that swift fabrication of PSCs through IPL can result in efficiencies exceeding 16% when the Perovskite film is annealed with aid of CH2I2 alkyl halide additive in the ambient with 60% relative humidity. In addition, the synergy of IPL-alkyl halide interaction for other perovskite chemistries is introduced. We show that achieving to PSCs exceeding 12% efficiency was possible when the perovskite and SnO2 ETL was annealed sequentiallymore »
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High energy density, high temperature, and low loss polymer dielectrics are highly desirable for electric energy storage, e.g., film capacitors in the power electronics of electric vehicles and high-speed trains. Fundamentally, high polarization and low dielectric loss are two conflicting physical properties, because more polarization processes will involve more loss mechanisms. As such, we can only achieve a delicate balance between high dielectric constant and reasonably low loss. This review focuses on achieving low dielectric loss while trying to enhance dielectric constants for dielectric polymers, which can be divided into two categories: extrinsic and intrinsic. For extrinsic dielectric systems, the working mechanisms include dipolar (e.g., nanodielectrics) and space charge (e.g., ion gels) interfacial polarizations. These polarizations do not increase the intrinsic dielectric constants, but cause decreased breakdown strength and increased dielectric loss for polymers. For intrinsic dielectric polymers, the dielectric constant originates from electronic, atomic (or vibrational), and orientational polarizations, which are intrinsic to the polymers themselves. Because of the nature of molecular bonding for organic polymers, the dielectric constant from electronic and atomic polarizations is limited to 2-5 for hydrocarbon-based insulators (i.e., band gap > 4 eV). It is possible to use orientational polarization to enhance intrinsic dielectric constantmore »
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