bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Atomic Layer Deposition for Fabrication of Solar Cells
Authors: Frohlich Karol , Mikolášek Miroslav , Subair Riyas , Nadazdy Vojtech , Rosová Alica , Precner Marian , Tasaltin Nevin , Alturk Elif , Tekin Emine , Aslan Emre , Ates Turkmen Tulin , Majková Eva 
Published: February 2020

Atomic layer deposition (ALD) is exceptional deposition technique because it allows for growth of high quality films on large are substrates at low deposition temperatures. In our contribution ALD was employed for preparation of transparent conducting electrodes and for encapsulation of fabricated solar cells.
Al-doped ZnO films were used for transparent conducting electrodes. Deposition was carried out at temperatures between 150 and 250 °C on Si and quartz substrates. Diethyl zinc and trimethyl aluminum were used as precursors and water vapors as reactant. Al-doping was performed by inserting Al2O3 cycles in ZnO growth. Deposition of 1 Al2O3 layer per 7 deposited ZnO layers gave the best results. Resistivity of the Al-doped ZnO films depended on the deposition temperature and film thickness. Transition electron microscopy revealed typical columnar growth of the films with fine grained polycrystalline region close to the substrate. The films with the thickness above 100 nm prepared at 250 °C showed resistivity of 1 mΩcm. This corresponds to the sheet resistance of 40 Ω/square. Hall measurement revealed electron concentration of 4*1020 cm-3 and mobility of 15 cm2Vs-1 for the films with resistivity of 1 mΩcm. Work function of 4.4 eV was measured by Kelvin probe. Optical transmittance of the films was higher than 80% in the wavelength range between 400 and 900 nm.
Al-doped ZnO transparent electrodes were used for fabrication of perovskite-type conventional planar solar cell. CH3NH3 PbI3 perovskite was used as absorbing layer, Spiro-OMeTAD as hole transport layer and Au/Ag as top contact layer. Properties of the solar cell with Al-doped ZnO electrode are compared with inverted planar solar cell using indium tin oxide as a transparent electrode.
Inorganic-organic hybrid perovskite solar cells suffer from poor stability in ambient atmosphere. Oxygen and moisture are believed to be reason for the solar cell degradation. To protect the cells against ambient atmosphere influence ALD prepared Al2O3 films were employed for encapsulation. Trimethyl aluminum was used as precursor while either water vapors or ozone were applied as reactants. Deposition of the Al2O3 films took place at 50°C.
Power conversion efficiency of the solar cell encapsulated by 24 nm Al2O3 thin film deposited using water vapors as reactant decreased to 60% while unprotected solar cell degraded down to 10% of its initial value after 20 days in ambient atmosphere. In our contribution we compare properties of perovskite solar cell encapsulated by ALD Al2O3 films prepared using water vapors or ozone as reactants.
Molybdenum Disulfides and Diselenides By Atomic Layer Deposition
Authors: Zazpe Raul , Prikryl Jan , Charvot Jaroslav , Dvorak Filip , Krbal Milos , Bures Filip , Macak Jan M. 
Published: February 2020

The success of graphene opened a door for a new class of chalcogenide materials with unique properties that can be applied in the semiconductor technology [1]. Monolayers of two-dimensional transition metal dichalcogenides (2D TMDCs) possess a direct band gap [2] that is crucial for optoelectronic applications. Additionally, the direct band gap can be easily tuned by either chemical composition or external stimuli. Next to the optoelectronic applications, where a monolayer planar structure is necessary to employ, a layer of standing flakes, which possesses a large surface area, can be used for hydrogen evolution [3] a photodegradation of organic dyes [4] or as electrodes in Li ion batteries [5].
In principle, TMDCs can be prepared by various top-down (e.g. exfoliation) and bottom-up techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) growth techniques [1]. MoS2, a typical representative of TMDCs, has been widely studied for many applications. Recently, the possibility to employ ALD as a technique to grow MoS2 has been reported. In these works (CH3)2S2 [6] or H2S [7, 8] were used as the S precursor and Mo(CO)6 [6], MoCl5 [7] or Mo(thd)3 [8] as the Mo precursors. From the practical point of view, MoSe2 is even more interesting than MoS2 since MoSe2 possesses a higher electrical conductivity than MoS2 [9, 10]. Recently, we have shown that ALD deposition of MoSe2 [11] or Mo-O-Se [12] using ((CH3)3Si)2Se as the Se precursor and the MoCl5 or Mo(CO)6, respectively, as the Mo precursors is feasible.
The presentation will focus on the synthesis of MoS2 and MoSe2 by ALD, their characterization and applications in various fields. Experimental details and some recent photocatalytic and hydrogen evolution results will be presented and discussed.
References:
[1] A. V. Kolobov, J. Tominaga, Two-Dimensional Transition-Metal, Dichalcogenides. Springer Series in Materials Science, Springer International Publishing AG, Switzerland 2016

[2] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, A. Kis, Nat. Nanotechnol. 2011, 6, 147.
[3] L. Wang, Z. Sofer, J. Luxa, M. Pumera, Adv. Mater. Interfaces
2015, 2, 1500041
[4] Y. Wu, M. Xu, X. Chen, S. Yang, H. Wu, J. Pan, X. Xiong, Nanoscale
2016, 8, 440
[5] D. Ilic, K. Wiesener, W. Schneider, H. Oppermann, G. Krabbes, J.Power Sources
1985, 14, 223
[6] Z. Jin, S.Shin,D.H.Kwon, S. J.Han,Y. S.Min,Nanoscale
2014, 6, 14453.
[7] L. K. Tan, B. Liu, J. H. Teng, S. Guo, H. Y. Low, K. P. Loh, Nanoscale
2014, 6, 10584
[8] M. Mattinen et al., Adv. Mater. Interfaces
2017, 4, 1700123.
[9] D. Kong, H. Wang, J. J. Cha, M. Pasta, K. J. Koski, J. Yao, Y. Cui, Nano Lett. 2013, 13, 1341.
[10] A. Eftekhari, Appl. Mater. Today
2017, 8.
[11] M. Krbal et al., Phys. Stat. Sol. RRL,
2018, 12, 1800023
[12] S. Ng et al., Adv. Mater. Interfaces
2017, 1701146.
(Invited) Organic Thermoelectric Materials and Devices
Authors: Yee Shannon K. 
Published: February 2020

Within the last 3 years, thermoelectric technologies have seen renewed global deployment providing unique solutions to pressing thermal problems. Today thermoelectric technologies are helping to ensure vaccines viably reach the most remote locations in the world, are providing personal comfort in wearable devices addressing medical circulatory conditions, and are being designed for integration into electric vehicles thereby reducing the global warming contributions of refrigerants in conventional air conditioning systems. The majority of these technologies have resulted from innovative engineers utilizing conventional materials in niche applications, however, additional societal contributions can be achieved by leveraging the large-area processability and abundance of polymer-based thermoelectrics.
Unfortunately, the material performance of polymer-based thermoelectric materials is lacking compared to their inorganic counterparts. To circumvent this challenge, composites or hybrid organic-inorganic materials are often employed in functional devices. Furthermore, while there is an abundance of p-type materials to select from, there are few air-stable n-type thermoelectric materials. Metal coordinated polymers (or metallo-organic polymers) are one promising class of thermoelectric materials where a metal (or semimetal) atom is present along the polymer backbone. This structure produces periodic centers of high electron density, which, when coupled to the vibrational modes (e.g., vibrons or phonons), could result in appreciable power factors. Both air-stable p-type and n-type metal coordinated polymers can be readily synthesized from abundant materials and are promising scalable alternatives to inorganics that leverage solution processing.
This talk will first provide a motivating overview of emerging thermoelectric technologies being developed. Next, this talk will discuss progress in synthesizing and controlling the thermoelectric properties of poly(nickel-ethenetetrathiolate) (i.e., Ni-ETT) and poly(nickel-tetrathiooxalate) (i.e., Ni-TTO), which are both air-stable n-type thermoelectric materials containing nickel along the polymer backbone. Next, this talk will discuss our work studying poly(3-alkyl-chalcogenophene), where the isovalent series of thiophene, selenophene, and tellurophene were investigated. Finally, this talk will introduce new thermoelectric device architectures, specifically printable and knittable devices, that are enabled by these materials. Throughout this talk emphasis will be placed on the engineering and scaling challenges, which have been overlooked in the pursuit of high performance materials, but are most critical to realizing thermoelectric devices.
(Invited) Electrochemical Synthesis of Chalcogen and Metal Chalcogenide Nanostructures for Thermoelectric Applications
Authors: To Dung , Seyedmahmoudbaraghani Saba , Yu Sooyoun , Myung Nosang Vincent 
Published: February 2020

In an attempt to overcome some of the drawbacks to the combustion of fossil fuel – such as a large carbon footprint and non-renewability – thermoelectric generators (TGs) have gained a considerable attention as a sustainable alternative technology, since they are environmentally friendly and have the ability of recycling abundant waste heat. Nanostructuring of thermoelectric materials can improve the dimensionless thermoelectric figure of merit (ZT) due to their abilities to independently control phonon scattering and energy-dependent scattering of electrical carriers. In comparison to different semiconductors for thermoelectric materials (e.g. IV and III-IV groups), chalcogens and metal chalcogenides show a lower lattice thermal energy due to their relatively large atomic masses and complex crystal structures, resulting in higher values of ZT.
Among various methods employed to synthesize chalcogen and metal chalcogenide nanostructures, electrochemical methods exhibit many advantages, such as the ability to control composition, grain size, and crystallinity including defects, and near room temperature deposition conditions. In this work, we will discuss the electrochemical synthesis of chalcogens and metal chalcogenides and correlate the structure with thermoelectric properties.
(Invited) Role of Anharmonicity on Thermoelectric Properties of Fully Dense Single-Crystalline Snse
Authors: Bhattacharya Sriparna , Chen Yang-Yuan , Rao Apparao M. 
Published: February 2020

Thermoelectric (TE) materials enable conversion of “waste” heat to electricity, leading to environmentally friendly solutions for power generation applications. The thermal-to-electrical energy conversion efficiency of a TE material is largely determined by its dimensionless figure-of-merit, ZT = S2σT/κ that consists of interrelated material properties, viz., the Seebeck coefficient (S), electrical conductivity (σ), and the thermal conductivity (κ). Recently, single-crystalline SnSe has attracted much attention due of its record high figure-of-merit ZT ≈ 2.6, [1] that was debated in subsequent reports due to the low mass density of these single crystals. [2] We performed structural, electrical, and thermal transport measurements on high-quality fully dense SnSe single crystals over a wide temperature range along the major crystallographic directions, that yielded a maximum ZT ~ 1 along one of the major crystallographic directions.[3] It is well known that phonon anharmonicity is one of the contributing factors that yields a remarkably low κ in binary SnSe. As an attempt to understand the role of phonon anharmonicity, we performed a combined temperature-dependent polarized Raman spectroscopic and heat-capacity study on fully dense single-crystalline SnSe, which revealed that the anharmonicity in SnSe is driven by soft optical modes in its bc plane. [4] This study provides a deeper understanding of the role of phonon-phonon scattering and anharmonicity leading to reported thermal transport properties of SnSe.
[1] Zhao, L.-D., Lo, S.-H., Zhang, Y., Sun, H., Tan, G., Uher, C., Wolverton, C., Dravid, V. P., Kanatzidis, M. G. Ultralow Thermal Conductivity and High Thermoelectric Figure of Merit in SnSe Crystals, Nature 2014, 508 (7496), 373–377.
[2] Wei, P. C., Bhattacharya, S., He, J., Neeleshwar, S., Podila, R., Chen, Y. Y., Rao, A. M., The Intrinsic Thermal Conductivity of SnSe, Nature 2016, E1–E2.
[3] Wei, P.C., Bhattacharya S., Liu Y-F., Liu F., He J., Tung Y-H., Yang C-C., Hsing C-R., Nguyen D.L., Wei C-M., Chou M-Y., Lai Y-C., Hung T-L, Guan S-Y., Chang C-S., Wu H-J., Lee C-H., Li W-H., Hermann R. P., Chen Y-Y., Rao A.M., Thermoelectric figure-of-merit of fully dense single crystalline SnSe, ACS Omega, 2019, 4 (3), 5442–5450.
[4] Liu F., Parajuli P., Rao R., Wei P.-C., Karunarathne A., Bhattacharya S., Podila R., He J., Maruyama B., Priyadarshan G., Gladden J. R., Chen Y.-Y., Rao A.M., Phonon Anharmonicity in single-crystalline SnSe, Phys. Rev. B 2018, 98, 224309.
(Invited) Thermoelectric Energy Conversion and Thermal Memristance and Switching
Authors: Urban Jeffrey J 
Published: February 2020

Heat and charge are fundamental energy carrying modes relevant to nearly all dynamic properties of interest in engineering, physics, and modern energy technologies. Here, I will discuss the design and understanding of transport properties in complex nanoscale systems where the dimensional constraints are changed systematically to reveal fundamental principles of heat and charge transport. The first part of this talk will focus on heat and charge transport in polymeric and hybrid nanomaterials, revealing the physical origins of scaling laws for charge transport in these materials. The second portion of my talk will discuss heat and charge transport in a different class of hybrid materials, the ever-popular perovskites. Here, I will briefly discuss possible origins for the ultra-low thermal conductivity observed in nanoscale samples, and new measurement approaches for resistive bulk perovskites. The final portion of my talk will briefly highlight strong deviations from the Wiedemann-Franz law in materials with electronic phase transitions, and possible applications of this phenomenology for novel devices exhibiting, for example, thermal rectification and thermal memristance.
Selected references:
1. Organic electronics: one model to rule them all, Nature Materials (2017)
2. Polymer morphology dominates over energy-dependent scattering in inorganic-organic hybrid thermoelectrics, Nature Communications (2018)
3. Ultralow thermal conductivity in all inorganic halide perovskites, PNAS (2017)
4. Phonon dispersion lifetimes of organic-inorganic hybrid perovskite CH3NH3PbI3 from Inelastic X-ray scattering (2018, in review).
5. Anomalously low electronic thermal conductivity in metallic vanadium dioxide, Science (2017)
6. Solid-state thermal rectification and negative differential thermal resistance using junctions of phase transition materials, Phys. Rev. Applied (2018)
(Invited) Electron Beam Induced Current Microscopy of Interfacial Barrier Effects in Al2O3/TiOx Resistive Switches
Authors: Hoskins Brian Douglas 
Published: February 2020

Resistive switching devices (ReRAM) represent a broad class of two-terminal continuously tunable resistors including memristors, phase change memory (PCM), valence change memory (VCM), and electrochemical metallization cells (ECM). Though these devices, especially PCM, are increasingly being commercialized by industry for use in next generation memories, they are also all actively studied for use as synaptic weights in next generation hardware-accelerated neuromorphic networks.
We have previously investigated Electron Beam Induced Current Microscopy as a means of reliably characterizing resistive switches. In that investigation, we observed surprising electronic effects, such as internal secondary electron emission, in addition to more traditional electron-hole pair separation, and we broke those up into constituent currents based on their origin through Monte-Carlo modeling of the electron beam-matter interaction.
Now, armed with a new understanding of the physics of EBIC imaging, we study the impact of manufacturing variations on resistive switches by continuously tuning the thickness of an Al2O3 interfacial barrier. Shifts in the apparent ratios of internal secondary electron emission from the top electrode to the bottom electrode and vice versa appear to indicate a continuous tuning of the apparent filament diameter as both a function of the injected current and the interfacial barrier thickness. This yields an apparent reduction in the current density, the primary effect of which is a reduction in the device damage from forming and a suppression of parasitic leakage currents imaged in devices without interfacial barriers.

Figure 1
(Invited) Trends in 3D Markets and Technology
Authors: Vardaman E. Jan 
Published: February 2020

Driven by performance, 3D packaging with through silicon vias (TSVs) has become a reality for memory and advanced logic. New versions are emerging.
High Bandwidth Memory (HBM) is one of the most important 3D IC developments in the last 10 years. In the last decade, stacked DRAM with through silicon vias has transitioned from a handful of research programs to rapidly increasing volumes.
Tezzaron has been providing small quantities of 3D ICs for high-speed memory applications since 2005. Micron, Samsung, and SK Hynix began producing DRAM stacks with TSVs in late 2014 and early 2015. Micron began shipments of its Hybrid Memory Cube (HMC) in 2015. DRAMs and the logic controller were interconnected with TSVs. HMC was packaged in a BGA and tested before assembly on the board. The HMC has been used in Intel’s Knights Landing. The silicon-on-insulator (SOI) logic layer was fabricated by GLOBALFOUNDRIES (which purchased IBM’s fab) and the memory was fabricated by Micron. Micron used a thermo-compression bond (TCB) process with a non-conductive film (NCF) underfill for its die stacking in the HMC. Thermal issues were a challenge. Today Samsung and SKHynix are providing HBM stacks to the industry and Micron is expected to ship products next year.
In February 2018, Samsung announced that its first “three-layer” stacked CMOS image sensors (CIS) were in mass production and found in the Galaxy S9/S9+. This follows Sony’s adoption of three-layer CIS technology one year earlier in February 2017. A third silicon layer in the form of DRAM is added to the pixel array and signal processing layers to significantly improve data readout speeds. These devices are manufactured with 3D IC technologies using TSVs, but Samsung and Sony use different design approaches. Technically speaking, Samsung’s solution is a two-layer image sensor with a stacked DRAM. Sony uses a true three-layer bonded approach. In its three-layer CIS technology, Sony places the DRAM between the pixel array die and the image processor, with all three layers interconnected using TSVs. The pixel array, DRAM, and logic wafers are manufactured with 90nm, 30nm, and 40nm processes, respectively.
While logic and memory stacks have remained elusive, Intel and TSMC have introduced new packaging technology with active interposers that are considered 3D. Intel has introduced its Foveros 3D integration technology as a form of heterogeneous system integration. The technology uses a 3D face-to-face stacking process. In the process, logic die are bumped and mounted on an active interposer next to memory or die with other functions. The active interposer can contain active parts of the system, such as the platform controller hub (PCH) that manages I/O for the system. The active interposer is mounted on a package substrate with solder bumps. TSMC has introduced its SoIC with face-to-face stacking and wafer-on-wafer (WoW). These technologies are front-end packaging and use direct or fusion bonding. The SoIC is a wafer with logic, with our without TSVs.
(Invited) Characteristics, Types and Development Direction of the Copper Foils for Batteries
Authors: Kim Young tae , Jun Sang hyun , Lee An na , Kim Ho gun , Kim Seon hwa 
Published: February 2020

Copper foil with low electrical resistivity was originally developed as an improved interconnect material for printed circuit boards. Since the development of lithium-ion batteries in the 1990s, copper foil has been used as anode current collectors in secondary batteries.
The control of copper electroplating conditions is a vital factor in the manufacturing of such copper foils. The manufacturing process comprises plating on a drum, surface treatment, and slitting. In particular, the core process of copper electroplating is the control of the additive recipe in copper electroplating. KCFT (Korea Copper Foil and FCCL Technologies) in South Korea is one of the leading companies in the world to develop these technologies.
Copper foil has the characteristics of double-sided shine. Since it is generally coated on both sides, the characteristics of both sides should be similar. For batteries, an anode is fabricated by coating an active material, such as natural or artificial graphite, on a copper foil. Batteries may be of the cylindrical, prismatic, or pouch types. The cylindrical-type battery is manufactured as a jelly roll, and the pouch-type battery is usually made by laminating. Depending on the properties of the copper foils, they can be classified as follows: general, high-strength, high-elongation, and high-strength and high-elongation types. The desired copper foil properties can be realized by controlling the grain size and its growth inhibition during heat treatment.
The direction of development for the copper foils for batteries is first to manufacture thin copper foil. The capacity or weight of the thin copper foils can be enhanced or reduced, respectively. Second, the stable handling of the battery manufacturing process should be realized.
Third, the copper foil productivity will be improved by adopting high-current-density plating or manufacturing longer and wider products. Finally, in order to improve the reliability of the batteries, copper foil swelling and breakage should be prevented by using high-strength materials and high-elongation materials for cylindrical-type batteries.
In conclusion, there is the need to develop of copper foil well based on the understanding of the role of additive and the understanding of the metal structures.