ACS Nano
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2021
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IF 15.881
Haoran Ning,Yan Zeng,Shouwei Zuo,Stephen V. Kershaw,Yi Hou,Yingying Li,Xiaona Li,Jing Zhang,Yuanping Yi,Lihong Jing,Jian Li,Mingyuan Gao
Ultrathin two-dimensional (2D) semiconductors exhibit outstanding properties, but it remains challenging to obtain monolayer-structured inorganic semiconductors naturally occurring as nonlayered crystals. Copper sulfides are a class of widely studied nonlayered metal chalcogenide semiconductors. Although 2D copper sulfides can provide extraordinary physical and chemical applications, investigations of 2D copper sulfides in the extreme quantum limit are constrained by the difficulty in preparing monolayered copper sulfides. Here, we report a subnanometer-thin quasi-copper-sulfide (q-CS) semiconductor formed upon self-assembly of copper(I)–dodecanethiol complexes. Extended X-ray absorption fine structure analysis revealed that the existence of Cu–Cu bonding endowed the layer-structured q-CS with semiconductor properties, such as appreciable interband photoluminescence. Theoretical studies on the band structure demonstrated that the optical properties of copper–dodecanethiol assemblies were dominated by the q-CS layer and the photoluminescence originated from exciton radiative recombination across an indirect band gap, borne out by experimental observation at higher temperatures, but with the onset of a direct emission process at cryogenic temperatures. The following studies revealed that the metal–metal bonding occurred not only in copper–alkanethiolate complex assemblies with variable alkyl chain length but also in silver–alkanethiolate and cadmium–alkanethiolate assemblies. Therefore, the current studies may herald a class of 2D semiconductors with extremely thin thickness out of nonlayered metal sulfides to bridge the gap between conventional inorganic semiconductors and organic semiconductors.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 7
·3576-3585
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IF 2.779
Gao Yue,Xiao Yu-bo,Liu Zhi-Quan,Liu Yang,Sun Rong
Cu-Cu bonding is always conducted at high temperature and high pressure in reductive atmosphere to eliminate the influence caused by oxidation. Herein, a novel low-pressure sinterable Cu nanoparticle (Cu-NPs) paste was developed using Cu Metal Organic Decomposition (MOD) ink as solvent and surface modifier. The Cu MOD ink in paste introduced in Cu nanoparticle paste not only eliminated the surface oxidation of Cu-NPs, but also modified Cu-NPs with Cu atoms due to the thermal decomposition during sintering process. As a result, robust Cu sinter joints for die-attachment could be realized at a low pressure of 0.4 MPa in non-reductive nitrogen atmosphere. Using the paste with 20 wt.% Cuf addition in solvent, a relative high shear strength of 17.1 MPa could be achieved at 300 °C, which is about 3.8 times higher than that sintered without MOD ink (4.5 MPa). When bonding temperature rose to 350 °C, even higher shear strength over 20 MPa was obtained. The bonding strength was comparable to the traditional Pb-5Sn solder alloy, promising its industrial potential.
研究领域:
材料科学
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电子工程
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纳米技术
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2017
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IF 3.133
Junjie Li,Xing Yu,Tielin Shi,Chaoliang Cheng,Jinhu Fan,Siyi Cheng,Tianxiang Li,Guanglan Liao,Zirong Tang
In this paper, we proposed a depressing bonding temperature method for Cu Cu bonding with nanoparticle paste. The paste was prepared by composting dominant Cu nanoparticles with Ag nanoparticles of lower sintering temperature , where the average nanoparticle size of Cu and Ag was 61.02 and 69.25 nm, respectively. The reliable bonding was successfully achieved at the temperature of 250 °C, the pressure of 1.12 MPa and the protection of Ar-H 2 gas mixture comparing with pure Cu nanoparticles paste. An optimal resistivity of sintered Cu-Ag composite nanoparticle paste can achieve 1.99 × 10 −7 Ω m with the 2:1 molar ratio of Cu to Ag, and the largest shear strength of the bonded Cu-Cu joint can reach 25.41 MPa. The underlying sintering mechanism of the composited nanoparticles was discussed. It suggests the compositing with Ag nanoparticles is a practical strategy towards lowering the bonding temperature for Cu-based interconnect. The experimental process can be easily implemented, the bonding temperature and the performance can satisfy the packaging requirements of current 3D-IC. The developed Cu-Ag composite nanoparticle paste is also promising for packaging of other thermal and force sensitive chips.
研究领域:
材料科学
·
电子封装技术
✓ 已验证
产品关联
DOI
高影响因子
Acta Metallurgica Sinica-English Letters
·
2025
·
IF 3.9
Wang Fengyi,Ma Jingyuan,Liu Jiahao,Ji Hongjun,Chen Hongtao
This study investigates using an antioxidation copper particle-free paste, formulated with self-reducing copper formate, for Cu-Cu bonding in electronic packaging applications. The research highlights the oxidation resistance of copper formate compared to traditional copper nanoparticles (CuNPs) and its ability to generate CuNPs through thermal decomposition. Experimental results demonstrate that the sintering process benefits from releasing reductive gases during decomposition, improving joint quality with reduced porosity and enhanced mechanical strength at elevated temperatures. Molecular dynamics simulations further elucidate the sintering behavior of CuNPs, providing significant insights into pore collapse, atomic mobility, and neck formation. The findings indicate that increased temperatures enhance surface and bulk diffusion, facilitating robust particle connections. Overall, this work establishes the potential of copper formate for achieving reliable interconnects in semiconductor devices, paving the way for advancements in material formulations for direct copper–copper bonding.
研究领域:
材料科学
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电子封装技术
·
计算材料学
✓ 已验证
产品关联
DOI
高影响因子
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