bluuebunny/crossref_metadata_2025_split huggingface dataset:
in Situ Observation of O-Metal Vibrations at Pt and Au Electrodes By Plasmonic Crystalline-Based SERS
Authors: Yagi Ichizo , Inokuma Kiyoshi 
Published: February 2020

For practical applications of polymer electrolyte fuel cell (PEFC), designing a high performance and low cost membrane electrode assembly (MEA) is necessary, and performance and cost of a MEA is closely related to the properties of catalysts. Improvement of cathode catalyst becomes a key, and fundamental understandings of cathode reaction mechanism has been essential.
For the reaction mechanism investigation, in situ, dynamic measurement tools should be required. We have been developing a combination of surface enhanced vibrational spectroscopic techniques, such as surface enhanced Raman scattering (SERS), surface enhanced infrared absorption spectroscopy (SEIRAS) and sum frequency generation (SFG) spectroscopy. Generator-collector regime in the electrochemical microchannel device has been also investigated to realize time-resolved measurement by detecting adsorbed intermediates during electrocatalytic reaction.
The recent development in nanofabrication technology affects in the field of plasmonics and various types of novel SERS-active substrates have been reported. We have already prepared the micrometer-scale inverse pyramid-type plasmonic crystalline SERS-active substrates [1-2] with flat (111)-oriented Au surfaces and strong SERS signals from self-assembled monolayers (SAMs) of thiophenol were detected[3]. Although SERS activity of the plasmonic crystalline substrate covered by Pt was not high, strong SERS signal has been reported at sphere segment void (SSV)-type plasmonic crystalline substrates covered with Pt or Pd.[4-5] By tuning the size and depth of SSVs, SERS signal from atomically thickness-controlled Pt thin film covering only the top most surfaces of Au-SSV has proved to give information about adorbates on Pt surfaces selectively. Furthermore, by remaining PS templates, only the Pt surface becomes electrochemically active and SERS intensity from Pt-rim is enhanced much higher. Electrochemical SERS measurement are also carried out in situ at Au- and Pt/Au-SSV substrates.

Acknowledgement

This work was supported by New Energy, Industrial Technology Development Organization (NEDO), Fuel Cell Promotion Office of the Agency of Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI).

References

[1] N.M.B. Perney et al., Opt. Exp., 14, 847 (2006)
[2] N.M.B. Perney et al., Phys. Rev. B, 76, 035426 (2007)
[3] N.Ohta et al., J. Phys. Chem. C, 112 , 17603 (2008)
[4]M.E. Abdelsalam et al., J. Am. Chem. Soc., 129, 7399 (2007)
[5] L. Cui et al., Phys. Chem. Chem. Phys., 11, 1023 (2009)
Electron Transfer Dynamics of Supramolecular Solar Cells
Authors: Gobeze Haptom B. 
Published: February 2020

Habtom B. Gobeze and Francis D’Souza*
Department of Chemistry, University North Texas, 1155, Union Circle, #305070, Denton, TX 76203-5017, USA
Francis.DSouza@unt.edu
The relation between energy positioning and adsorption geometry on the electron transfer dynamics of donor-acceptor photosynthetic model compounds immobilized mesoporous TiO2 surface will be presented. Novel Zn-porphyrin (ZnP) and Zn-phthalocyanine (ZnPc) electron-donor and fullerene (C60) electron-acceptor bearing photosynthetic model compounds are designed to build supramolecular dye-sensitized solar cells (DSSC). It has been found that the solar cell efficiencies normalized for surface coverage (ηrel) are affected by the molecular spacer connecting the porphyrin sensitizer to the TiO2 surface, orientation of the dye molecule, the sensitization conditions (solvent and time) and dye aggregation. Ultrafast transient absorption spectroscopy shows that the forward and reverse electron transfer rates are strongly dependent on the spacer and sensitization conditions. These results also indicate that the electron transfer between sensitizer and TiO2 occurs “through-space” rather than “through-molecular spacer”. Implications of these findings for optimized solar energy/fuel production, and future sensor/biosensor development will be discussed.
Functionalized Porphycenes
Authors: Jux Norbert , Brenner Wolfgang 
Published: February 2020

Functionalized porphycenes

Norbert Jux, Wolfgang Brenner

Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany

Porphycenes were first synthesized by the group of Emanuel Vogel in 1986.[1] Over the years new synthetic routes have been introduced and since then a variety of porphycenes has been generated[2]and used to some extent in the fields of catalysis, protein mimicry and materials science. Due to their intense absorptions in the long-wavelength region, porphycenes are interesting candidates as dyes in photovoltaic applications.
We have started to look into the preparation of functionalized porphycenes with respect to charges, anchor groups, and arylated materials.
Image
Here, we wish to report on the synthesis and some photovoltaic device formation[3,4]of our novel porphycenes.

References

[1] E. Vogel, M. Köcher, H. Schmickler, J. Lex, Angew.
Chem. Int. Ed.
1986, 25, 257-259.
[2] D. Sánchez-García, J.L. Sessler, Chem. Soc. Rev.
2008, 37, 215-232.
[3] W. Brenner, J. Malig, R.D. Costa, D.M. Guldi, N. Jux, Adv. Mater.
2013,
25, 2314–2318.
[4] R.D. Costa, J. Malig, W. Brenner, N. Jux, D.M. Guldi, Adv. Mater.
2013,
25, 2600–2605.
Designing a Precious Metal-Free Catalyst for Purification of Automotive Exhausts: The Dissociation of NO on Cu2O(111) and CuO(110) Surfaces
Authors: Kasai Hideaki , Padama Allan Abraham Bustria , Moreno Joaquin Lorenzo Valmoria 
Published: February 2020

Nitrogen oxide (NOx) is a by-product of fossil fuel combustion and forms nitric acid in the air, which is the main reason for acid rain and smog. The interaction of NOxmolecule on catalysts is the rate-limiting step for its reduction process and is the motivation for recent investigations [1, 2]. Three-way catalysts, which are composed of precious metals such as Rh, Pd and Pt, work well for such purpose; however, their efficiency is compensated by their expensive cost. Therefore, a more readily available and inexpensive material with comparable, if not better, catalytic performance is a major concern among automobile companies and researchers.
In our recent work [3-6], we established the promising performance of Cu-based catalysts for the dissociation of NO by employing Computational Materials Design® based on density functional theory. Our results show that NO dissociation on Cu-terminated Cu2O(111) and Cu-terminated CuO(110) surfaces is comparable with Rh(111) [4], which is characterized by a transition state lying below the reference energy (surface and gas phase NO). This phenomenon is attributed to the modified electronic structure of the surface Cu atoms of Cu oxide surfaces in comparison with that of Cu(111). Specifically, the initially low-lying density of states (d orbital) of the surface Cu atoms in Cu(111) are shifted towards the Fermi energy in the Cu oxide systems. In comparison with Rh(111), the calculated NO dissociation barriers are lower on Cu oxide catalysts. Furthermore, the binding energy of co-adsorbed N and O atoms is weaker on Cu oxides, which is favorable for subsequent reactions (Fig. 1). Likewise, our experimental collaborators have verified that Cu oxides can be better catalysts than Rh, Pd and Pt for the purification of exhaust gases.
Indeed, this study has gained recognition as it ranked first in the Technology Trend Survey (Nikkei Shinbun) and was also publicly acknowledged in Japan. The details of our work, as well as the oxidation of CO in the presence of dissociated NO on Cu oxide surface will be discussed in the meeting.
References:
[1] F. Oemry, H. Kasai et al., J. Nanosci. Nanotechnol.11 (2011) 2844.
[2] N.T. Quang, H. Kasai et al., Comput. Mater. Sci. 47 (2009) 111.
[3] H. Kasai, A.A.B. Padama et al., J. Jpn. Petrol. Inst. 56 (2013) 357.
[4] H. Kishi, H. Kasai et al., J. Phys.: Condens. Matter 24 (2012) 262001.
[5] A.A.B. Padama, H. Kasai et al., J. Phys.: Condens. Matter 24 (2012) 175005.
[6] J.L.V. Moreno, A.A.B. Padama, H. Kasai, CrystEngComm (2013) submitted.
Tailoring Porphyrin (Nano)Structures
Authors: Senge Mathias O. 
Published: February 2020

Many possibilities exist to modify the structure of porphyrins. These include variation of the central metal, N-substitution or modulation of the macrocyclic π-system. Recent years have seen a surge in π-annulated systems while a more established approach is the synthesis of nonplanar porphyrins via peripheral macrocycle interactions. Any of these strategies results in porphyrin systems with altered structure, conformation and physicochemical properties. What is lacking is true ‘conformational design’ of porphyrins, i.e., the use of the recent advances in organometallic chemistry in conjunction with structural studies to yield functional systems with predesigned conformations. Such an approach would aid development of new optical materials and catalysts.
Similarly, an expanding body of studies on porphyrin nanomaterials on surfaces is beginning to reveal how surface/macrocycle interactions alter the chemical properties of porphyrins. Metallation and metal exchange reactions are possible and specific types of porphyrin nanostructures are now accessible via logical 2D synthesis on metal surfaces. Initial studies of porphyrin-graphene interactions indicate that a combination of tailor made porphyrins with specific macrocycle-surface interactions can yield functional nanomaterials.
Artificial Photosynthetic Devices Based on Phthalocyanines
Authors: Torres Tomas , Ballesteros Beatriz , Bottari Giovanni , Setaro Francesca , Ince Mine , Pardo Rodriguez Virtudes , Tejerina Lara , sanchez Carballo Maria , Medel Maria , Aljarilla Ana , Suanzes Pita Juan , Urbani Maxence , Trukhina Olga 
Published: February 2020

Phthalocyanines (Pcs) [1-3] are among the few molecules that reveal an intense NIR absorption and therefore, constitute promising dyes in molecular photovoltaics [4]. Pcs have emerged also as excellent light harvesting antennas for incorporation into donor-acceptor systems, mainly in connection with carbon nanostructures as acceptor moieties [3]. During this talk an overview of the results obtained by our group in Madrid will be given.

References

1. G. de la Torre, C. G. Claessens, T. Torres, Chem. Commun.2000 (2007).
2. (a) M.V. Martínez-Díaz, G. de la Torre; T. Torres T. Chem. Commun. 46, 7090 (2010); (b) M. E. Ragoussi, M. Ince, T. Torres, T. Eur. J. Org. Chem. 29, 6475 (2013).
3. G. Bottari, G. de la Torre, D. M. Guldi, T. Torres, Chem. Rev.
110, 6768 (2010).
4. M. E. Ragoussi, J.J. Cid, J.H. Yum, G. de la Torre, D. Di Censo, M. Graetzel, M.K. Nazeeruddin, T. Torres, Angew. Chem. Int. Ed. Eng. 51, 4375 (2012).
Dielectric/Si Interface Quality Characterization Using Room Temperature Photoluminescence
Authors: Yoo Woo Sik , Kim Byoung Gyu , Jin Seung Woo , Ishigaki Toshikazu , Kang Kitaek 
Published: February 2020

Advanced metal-oxide-semiconductor (MOS) and metal-insulator-semiconductor (MIS) devices employ ultra thin dielectric gate layers. The physical dimensions are in the range of single digit to double digit nanometers. The effective oxide thickness (EOT) is significantly less than 10 nm. Pure SiO2 or combinations of SiO2and SiN layers are typically used as gate dielectrics. High dielectric constant materials (high-k dielectrics) and metal gates are also frequently used, depending on chip design.
Physical dimensions of dielectric layer(s) are typically measured using ellipsometry and high resolution cross-section transmission microscopy (HRXTEM). Electrical characteristics are typically characterized using either contact or non-contact C-V and I-V measurements tools. Non-contact characterization techniques are generally preferred for in-line monitoring applications. However, spatial resolution of non-contact C-V and I-V measurement techniques is in the range of a few millimeters, which are 3 orders of magnitude larger than typical dimensions of actual devices. High spatial resolution, non-contact dielectric/Si interface quality characterization techniques must be developed.
In this paper, ultra thin (~7 nm) SiO2/Si and ultra thin SiN/SiO2/Si wafers were prepared by low pressure thermal chemical vapor deposition (CVD) and thermal oxidation. Dielectric/Si interface quality was characterized by room temperature spectroscopic photoluminescence (PL) measurements. The PL intensity and spectra from Si were measured under different excitation wavelengths which have different probing depths. PL is an optical characterization technique which does not require any sample preparation and physical contact. Typical spatial resolution is in the range of a few microns. Small variations in dielectric/Si interface quality modulates electronic carrier behaviors significantly which results in large variations in PL intensity and spectra.
Significant variations in PL intensity and spectra were measured from ultra thin (~7 nm) SiO2/Si wafers prepared by and low pressure thermal CVD and thermal oxidation. Si wafers with thermal oxide films generally showed significantly stronger PL intensity than Si wafers with thermal CVD grown oxide films (Fig. 1). Trends in PL intensity and spectra indicate the SiO2/Si interface quality of the thermally oxidized SiO2/Si is superior to that of the thermal CVD grown SiO2/Si (Fig. 2). PL characterization is found to be very sensitive to the integrity of dielectric/Si interface and thus, is promising as an in-line, non-contact interface quality monitoring technique.
The excitation wavelength dependence of PL intensity and spectra of SiO2/Si and SiN/SiO2/Si will be discussed along with conventional physical and electrical characterization results.
Measuring CET of High-k Dielectrics with Novel Kinetic Approach Using Micro-Site Corona – Kelvin Method
Authors: Marinskiy Dmitriy , Loy Thye Chong , Yeh H. C. , Wilson Marshall , Lagowski Jacek 
Published: February 2020

Freshly deposited surfaces of high-k dielectrics revealed a new set of challenges for monitoring capacitance equivalent thickness, CET, using micro-site corona – Kelvin metrology. Specifically, ions deposited by corona discharge may have a queue-time dependent high surface diffusivity, which causes charge spreading away from charging spot under the Kelvin voltage probe. This could result in underestimation of dielectric thickness and unrepeatable results.
To overcome this problem, we have developed a kinetic approach based on the analysis of the surface voltage transient after point source corona charging. The mathematical solution of the two-dimensional diffusion equation enables fitting of the voltage transient and reliable determination of two parameters: the surface diffusion coefficient and the dielectric capacitance. The latter one gives CET. The kinetic approach was applied to HfO2 layers deposited by atomic layer deposition. Repeatable CET measurements for a range of high-k surface conditions and thicknesses are presented. Elimination of queue-time dependence achieved with the novel kinetic approach is a significant advantage for fab-line monitoring.
Requirements and Difficult Challenges for Packaging in the Era of “More Than Moore”
Authors: Bottoms Wilmer R 
Published: February 2020

The benefits of Moore’s Law are slowing as we reach the limits of scaling imposed by the laws of physics. The advantages of higher speed and lower power requirements no longer scale with device feature size. One approach to increase functional density as the benefits of scaling slow is to incorporate functional diversification within a single package. Combining analog, RF, power devices, optical devices, MEMS and other devices types into a single package enables this functional diversification. System-in-package (SiP) architectures combining these components with logic and memory that follow Moore’s Law offsetting much of the decreased benefits of scaling has been called “More than Moore”.
This sounds very simple but there are many difficult challenges that arise in incorporating components with diverse requirements into a single, high density package and delivering the reliable performance demanded by the markets. These challenges include:

Lack of adequate modeling and simulation tools for complex SiP packages

Thermal management with increased thermal density, “hot spots”, etc.

Stress and warpage associated with CTE differences between various components

Cross talk between components

Protecting fragile components such as thinned die, MEMS and compound semiconductors

Maintaining power integrity with widely varying power requirements of various components

Requirements for both hermitic and open packages for sensor environmental access

There are many other challenges as we increase the density of components and interconnect wiring, incorporate heterogeneous integration of both component types and materials used, support a wide range of supply voltages from below 400mV to several volts and incorporate 3D integration. Perhaps the most difficult challenge is to meet these expanding requirements while continuously driving down the cost per function demanded by the markets. Traditionally, packaging has not scaled down in cost with shrinking geometries as quickly as CMOS integrated circuits. Introduction of complex “More than Moore” SiP packages makes this cost challenge much more difficult.
The ITRS was established to forecast the difficult challenges that must be met to satisfy future requirements with sufficient lead time to allow implement a solution. This process has been very successful and, since the beginning of the ITRS, packaging challenges have not prevented continued end user product cost reduction and performance increases. The packaging solutions needed now to continue these improvements in size, cost and performance cannot be delivered by continuing down a known path as we did with CMOS scaled integrated circuits.

Everything has to change.
This includes package architectures, design and simulation tools, materials, connections, etc. Many of these changes are underway but there is much more to come. Specific examples of requirements, challenges and potential solutions for packaging in the Era of ‘More than Moore” identified in the 2013 ITRS will be discussed.
(Invited) Microwave-Based Metrology Platform Development: Application of Broad-Band RF Metrology to Integrated Circuit Reliability Analyses
Authors: You Lin , Okoro Chukwudi A , Ahn Jung-Joon , Kopanski Joseph J. , Obeng Yaw S. 
Published: February 2020

Three dimensional stacked integrated circuits (3D-ICs), achieved using through-silicon vias (TSV), is an enabler for the continued miniaturization, increased performance and functional diversification of microelectronic devices. However, their introduction to the market has been hindered by many reliability challenges; in particular, stress related failures in this new technology are significantly worse than the traditional planar integrated circuits. For example, the large mismatch in the coefficient of thermal expansion (CTE) of the silicon matrix (~2.3 ppm/ºC) and the copper TSV (~17 ppm/ºC) interconnects, results in the buildup of stresses. This introduces a new reliability challenges such as the degradation of transistors and other front-end-of-line (FEOL) devices, in close proximity to the TSVs [2].
By and large, stress is the root cause of most microelectronic devices reliability failures; it has been reported that 65% of all microelectronic device failures are thermo-mechanical related, mostly due to thermally induced stresses and strains stemming from the mismatch in the neighboring dissimilar materials [1]. The stress evolution leads to stress buildup, resulting in the generation of defects such as cracks, voids, delamination, plastic deformation, warpage and buckling. These damages could ultimately lead to open or short circuits in the microelectronic chip, resulting in their failure.
Metrology for accurate understanding and quantification of the impact of stress evolution in 3D-ICs structures is key to addressing stress-related reliability challenges associated with the 3D-IC technology. In this presentation, we discuss our attempts to identify and characterize types of performance-limiting defects in three-dimensional (3-D) nanoelectronic devices, with special focus on 3-D interconnects, and relate the defects to the evolution of stress, where and why they form within the samples studied. In addition, we discuss non-destructive techniques for identifying such performance-limiting defects, without interrupting the responsible mechanistic phenomena [3].

References

B. Wunderle, B. Michel et al, “Progress in Reliability Research in the Micro and Nano Region.” Microelectronics and Reliability, Vol. 46, pp. 1685-1694.

A. Mercha et al, Comprehensive Analysis of the Impact of Single and Arrays of Through Silicon Vias induced Stress on High-k / Metal Gate CMOS Performances”, International Electron Devices Meeting (IEDM), Dec. 2010, San Francisco, CA, USA, pp. 2.2.1 -2.2.4.

C. Okoro et al., “Accelerated Stress Test Assessment of Through-Silicon Via using RF Signals,” IEEE Transaction on Electron Devices. Vol. 60, No.6, 2013, pp 2015-2021
The Effect of Amino Acids on Step Height Reduction in STI CMP
Authors: Kim Kijung , Seo Jihoon , Moon Jinok , Kim Yehwan , Kim Sangkyun , Paik Ungyu 
Published: February 2020

Shallow trench isolation (STI) process has been a crucial technology to isolate the transistors in ultra large scale integration (ULSI) device [1]. In STI process, step height of dielectric material is inevitably formed after gap-filling process due to the different pattern density. Chemical mechanical planarization (CMP) process has been employed to remove the step height. Remaining step height would cause defects such as dishing and erosion, therefore the reduction of step height can be considered as one of the critical issues in STI-CMP process.
Several groups have studied about the step height reduction using ceria due to its high removal rate of SiO2 [2]. Lim et al. reported that the effect of particle size on step height reduction. They showed that the large particle size could improve the step height reduction by its high removal rate. Recently, the needs of small particle have been increased because the defect control has been more important as the design rule is getting narrow. Therefore, it is inevitable to develop new methodology to enhance the step height reduction. Here, we used different amino acid to modify the surface of ceria and enhance the interaction between the ceria slurry and SiO2.
We investigated the effect of ceria slurries prepared with L-serine, proline, glutamine and amino butyric on step height reduction. We calculated the interaction forces between ceria with different amino acids and SiO2 film by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The result shows that ceria slurry with L-serine or proline has higher attractive interaction forces with SiO2 than the slurry with glutamine or amino butyric acid (Fig. 1).
The results of SiO2 pattern as different pattern density and line width show that the ceria slurry with L-serine or proline produces higher step height reduction than the slurry with glutamine or amino butyric (Fig. 2). As a result, we found that the high interaction forces between ceria slurry and SiO2 contribute to high step height reduction and it is stronger in case of the slurry with L-serine or proline than the slurry with glutamine and amino butyric acid.