Hybrid Thin-Film Materials Combinations for Complementary Integration Circuit Implementation

Beyond conventional silicon, emerging semiconductor materials have been actively investigated for the development of integrated circuits (ICs). Considerable effort has been put into implementing complementary circuits using non-silicon emerging materials, such as organic semiconductors, carbon nanotubes, metal oxides, transition metal dichalcogenides, and perovskites. Whereas shortcomings of each candidate semiconductor limit the development of complementary ICs, an approach of hybrid materials is considered as a new solution to the complementary integration process. This article revisits recent advances in hybrid-material combination-based complementary circuits. This review summarizes the strong and weak points of the respective candidates, focusing on their complementary circuit integrations. We also discuss the opportunities and challenges presented by the prospect of hybrid integration.

Study on chemical synthesis of SnSSe nanosheets and nanocrystals

Two kinds of raw material combination for the hot injection method were investigated for the chemical synthesis of SnSSe nanosheets and nanocrystals, which are low-toxic optoelectronic materials. When SnSe quantum dots were synthesized by mainly using oleic acid as Se precursor solvent, the quantum dots changed from spherical to cubic as the size increased. The growth condition dependence of the nanocrystal formation process was discussed. When SnSSe nanocrystals were synthesized by mainly using trioctylphosphine as Se precursor solvent, it was found that the nanocrystal shape changed from dot to rod or sheet by reducing the proportion of S. The bandgap energy did not simply depend on the composition ratio of S but was affected by the change in the nanocrystal shape depending on the quantum confinement effect.

Design criteria for the pin-foot ratio for joining adhesion-incompatible polymers using pin-like structures in vibration welding process

Joining technologies have a crucial role in the product development process, e.g. to achieve local part properties or functional integrations. This often requires multi-material joints, which are challenging for conventional joining processes. Therefore, innovative processes are needed to generate bonds between adhesion-incompatible material combinations, such as joining using pin-like structures in the vibration welding process. Investigations into this novel process have provided initial findings; however, a specific pin design is not possible at this time. For this reason, the influence of the pin-foot width of the two joining partners was analyzed numerically by simulation. The results of the simulation were validated by experimental tests. The investigations show, that the simulation model is suitable for predicting the bond quality as well as the fracture behavior of the multi-material joint based on pin-like structures. The developed correlations between material, pin-like structure, and resulting bond quality allow design criteria for the pin-like structures to be derived. These allow a specific dimensioning of the pin-foot ratio depending on the used material combination. Thus, for example, the fracture behavior of the multi-material connection can be selectively adjusted, as well as the bond strength can be maximally utilized.

DERIVATION OF MOTIVATORS FOR THE USE OF ALUMINUM FOAM SANDWICH AND ADVANTAGEOUS APPLICATIONS

Aluminum foam sandwich (AFS) is an innovative material combination for designing lighter products and has many advantages such as a high bending stiffness at a low density and good energy absorption properties. Although the material is ready for series production, the number of industrial applications is low because of the high costs of the material, a lack of design knowledge and missing reference applications. This paper focuses on the aspect of missing reference applications and how to improve this situation in order to give designers an idea of where the material could be used profitably and to provide the basis for a selection method. Therefore, a systematic literature review is carried out to identify profitable applications with their respective advantages. As a main result, a set of motivators for the use of aluminum foam sandwich is developed, which will support the designer in evaluating the potential use of aluminum foam sandwich.

Influence of Material Properties on Interfacial Morphology during Magnetic Pulse Welding of Al1100 to Copper Alloys and Commercially Pure Titanium

During magnetic pulsed welding (MPW), a wavy interface pattern can be observed. However, this depends on the specific material combination being joined. Some combinations, e.g., steel to aluminum, simply provide undulating waves, while others, e.g., titanium to copper, provide elegant vortices. These physical features can affect the strength of the joint produced, and thus a more comprehensive understanding of the material combination effects during MPW is required. To investigate the interfacial morphology and parent material properties dependency during MPW, tubular Al1100 and various copper alloy joints were fabricated. The influence of two material properties, i.e., yield strength and density, were studied, and the interface morphology features were visually investigated. Results showed that both material properties affected the interface morphology. Explicitly, decreasing yield strength (Cu101 and Cu110) led to a wavy interface, and decreasing density (Cu110 and CP-Ti) resulted in a wave interface with a larger wavelength. Numerical analyses were also conducted in LS-DYNA and validated the interface morphologies observed experimentally. These simulations show that the effect on shear stresses in the material is the cause of the interface morphology variations obtained. The results from this research provide a better fundamental understanding of MPW phenomena with respect to the effect of material properties and thus how to design an effective MPW application.

Verschleißverhalten von additiv gefertigten Kunststoff-Kunststoff-Gleitpaarungen

For industrial applications, additive manufacturing becomes more and more important due to its unrivaled design and materials freedom. In this light, additively manufactured polymer-polymer sliding combinations gain increasing interest for manifold tribological applications. This potential can be fully exploited, e.g., by using tribologically tailored compounds. For additive manufacturing not only the sliding combinations but also the understanding of the influence of printing parameters are important. Thus, this work is a first investigation of commercially available tribological compounds regarding their wear behavior by means of the ball-prism wear test. On that basis, influences of printing orientation and material combination on the wear behavior are investigated. In addition, interactions of these parameters will be discussed. Finally, the challenges of test specimen production as well as wear measurements are considered.

EXPERIMENTAL INVESTIGATION ON THE RUBBING PROCESS OF LABYRINTH SEALS CONSIDERING THE MATERIAL COMBINATION

Labyrinth seals are used to prevent and control the mass flow rate between rotating components. Due to thermally and mechanically induced expansions during operation and transient flight maneuvers, a contact, the so-called rubbing process, between rotor and stator cannot be excluded. A large amount of rubbing process data concerning numerical and experimental investigations is available in public literature as well as at the Institute of Thermal Turbomachinery (ITS). The investigations were carried out for different operating conditions, material combinations, and component geometries. In combination with the experiments presented in this paper, the effects of the different variables on load due to rubbing are compared, and discussed with the focus lying on the material combination. The influence of the material on the loads can be identified as detailed as never before. For example, the contact forces in the current experiments are higher due to a higher temperature resistance of Young's modulus. The analysis will also be based on the rubbing of turbine blades. Design guidelines are derived for labyrinth seals with improved properties regarding tolerance of rub events. Based on the knowledge obtained, guidelines for designing reliable labyrinth seals for future engines are discussed.