Boosting hot electron flux and catalytic activity at metal-oxide interfaces of PtCo bimetallic nanoparticles

Despite numerous studies, the origin of the enhanced catalytic performance of bimetallic nanoparticles (NPs) remains elusive because of the ever-changing surface structures, compositions, and oxidation states of NPs under reaction conditions. An effective strategy for obtaining critical clues for the phenomenon is real-time quantitative detection of hot electrons induced by a chemical reaction on the catalysts. Here, we investigate hot electrons excited on PtCo bimetallic NPs during H-2 oxidation by measuring the chemicurrent on a catalytic nanodiode while changing the Pt composition of the NPs. We reveal that the presence of a CoO/Pt interface enables efficient transport of electrons and higher catalytic activity for PtCo NPs. These results are consistent with theoretical calculations suggesting that lower activation energy and higher exothermicity are required for the reaction at the CoO/Pt interfac

Superaerophobic hydrogels for enhanced electrochemical and photoelectrochemical hydrogen production

The efficient removal of gas bubbles in (photo)electrochemical gas evolution reactions is an important but underexplored issue. Conventionally, researchers have attempted to impart bubble-repellent properties (so-called superaerophobicity) to electrodes by controlling their microstructures. However, conventional approaches have limitations, as they are material specific, difficult to scale up, possibly detrimental to the electrodes' catalytic activity and stability, and incompatible with photoelectrochemical applications. To address these issues, we report a simple strategy for the realization of superaerophobic (photo)electrodes via the deposition of hydrogels on a desired electrode surface. For a proof-of-concept demonstration, we deposited a transparent hydrogel assembled from M13 virus onto (photo)electrodes for a hydrogen evolution reaction. The hydrogel overlayer facilitated the elimination of hydrogen bubbles and substantially improved the (photo)electrodes' performances by maintaining high catalytic activity and minimizing the concentration overpotential. This study can contribute to the practical application of various types of (photo)electrochemical gas evolution reactions

Variation-aware advanced CMOS devices and SRAM

This book provides a comprehensive overview of contemporary issues in complementary metal-oxide semiconductor (CMOS) device design, describing how to overcome process-induced random variations such as line-edge-roughness, random-dopant-fluctuation, and work-function variation, and the applications of novel CMOS devices to cache memory (or Static Random Access Memory, SRAM). The author places emphasis on the physical understanding of process-induced random variation as well as the introduction of novel CMOS device structures and their application to SRAM. The book outlines the technical predicament facing state-of-the-art CMOS technology development, due to the effect of ever-increasing process-induced random/intrinsic variation in transistor performance at the sub-30-nm technology nodes. Therefore, the physical understanding of process-induced random/intrinsic variations and the technical solutions to address these issues plays a key role in new CMOS technology development. This book aims to provide the reader with a deep understanding of the major random variation sources, and the characterization of each random variation source. Furthermore, the book presents various CMOS device designs to surmount the random variation in future CMOS technology, emphasizing the applications to SRAM

Advanced MOSFET Designs and Implications for SRAM Scaling

Continued planar bulk MOSFET scaling is becoming increasingly difficult due to increased random variation in transistor performance with decreasing gate length, and thereby scaling of SRAM using minimum-size transistors is further challenging. This dissertation will discuss various advanced MOSFET designs and their benefits for extending density and voltage scaling of static memory (SRAM) arrays. Using threedimensional (3-D) process and design simulations, transistor designs are optimized. Then, using an analytical compact model calibrated to the simulated transistor current-vs.-voltage characteristics, the performance and yield of six-transistor (6-T) SRAM cells are estimated. For a given cell area, fully depleted silicon-on-insulator (FD-SOI) MOSFET technology is projected to provide for significantly improved yield across a wide range of operating voltages, as compared with conventional planar bulk CMOS technology. Quasi-Planar (QP) bulk silicon MOSFETs are a lower-cost alternative and also can provide for improved SRAM yield. A more printable "notchless" QP bulk SRAM cell layout is proposed to reduce lithographic variations, and is projected to achieve six-sigma yield (required for terabit-scale SRAM arrays) with a minimum operating voltage below 1 Volt

How Social Entrepreneurs Affect Performance of Social Enterprises in Korea: The Mediating Effect of Innovativeness

Schumpeter argued that entrepreneurship brings about creative destruction in capitalist economies. South Korea enacted the Social Enterprise Promotion Act in 2007 to promote corporate social enterprise. However, despite government support, social enterprises in Korea are not successful, especially in social and economic performance, which is defined as the social and economic value that social enterprises should pursue. A questionnaire survey was conducted among 100 social entrepreneurs, and the structural equation model was used as the research method. The results of the analysis are as follows. Openness and innovativeness have a positive direct impact on economic as well as social performance. In addition, openness and innovativeness play a mediating role not only in social performance, but also in economic performance. This paper suggests theoretical and policy implications based on the above analysis

How Social Entrepreneurs Affect Performance of Social Enterprises in Korea: The Mediating Effect of Innovativeness

Schumpeter argued that entrepreneurship brings about creative destruction in capitalist economies. South Korea enacted the Social Enterprise Promotion Act in 2007 to promote corporate social enterprise. However, despite government support, social enterprises in Korea are not successful, especially in social and economic performance, which is defined as the social and economic value that social enterprises should pursue. A questionnaire survey was conducted among 100 social entrepreneurs, and the structural equation model was used as the research method. The results of the analysis are as follows. Openness and innovativeness have a positive direct impact on economic as well as social performance. In addition, openness and innovativeness play a mediating role not only in social performance, but also in economic performance. This paper suggests theoretical and policy implications based on the above analysis

Advanced MOSFET Designs and Implications for SRAM Scaling

Continued planar bulk MOSFET scaling is becoming increasingly difficult due to increased random variation in transistor performance with decreasing gate length, and thereby scaling of SRAM using minimum-size transistors is further challenging. This dissertation will discuss various advanced MOSFET designs and their benefits for extending density and voltage scaling of static memory (SRAM) arrays. Using threedimensional (3-D) process and design simulations, transistor designs are optimized. Then, using an analytical compact model calibrated to the simulated transistor current-vs.-voltage characteristics, the performance and yield of six-transistor (6-T) SRAM cells are estimated. For a given cell area, fully depleted silicon-on-insulator (FD-SOI) MOSFET technology is projected to provide for significantly improved yield across a wide range of operating voltages, as compared with conventional planar bulk CMOS technology. Quasi-Planar (QP) bulk silicon MOSFETs are a lower-cost alternative and also can provide for improved SRAM yield. A more printable "notchless" QP bulk SRAM cell layout is proposed to reduce lithographic variations, and is projected to achieve six-sigma yield (required for terabit-scale SRAM arrays) with a minimum operating voltage below 1 Volt

Classifying Social Enterprises with Organizational Culture, Network and Socioeconomic Performance: Latent Profile Analysis Approach

Culture is a key driving force in enhancing organizational performance. The results of recent studies indicate the importance of managers having the capacity to understand organizational culture and link it to organizational performance improvement. This study aims to examine the relationship between organizational culture and performance improvement in social enterprises. In the past, organizational culture was described in terms of a single dimension, but it is now understood that different cultures reflect different values and beliefs, in a seemingly contradictory manner, and can coexist within any given organization. We analyze the relationships among social enterprise networking, performance, and organizational culture, using the four organizational culture classifications of the competing values framework, which reflects recent perspectives. A survey was conducted among 100 social entrepreneurs, and latent profile analysis was applied to the data. The analytical results identify four latent profiles—namely, strong-balanced, weak-balanced, hierarchical, and group-dominant—and show that a balanced culture fosters high-level socioeconomic performance

How Social Entrepreneurs’ Value Orientation Affects the Performance of Social Enterprises in Korea: The Mediating Effect of Social Entrepreneurship

Efforts have been made to improve the performance of social enterprises through many studies on social entrepreneurs and social entrepreneurship. However, previous studies have conceptualized social entrepreneurship based on researches on commercial entrepreneurs. In addition, the scale used in the analysis of social entrepreneurship focuses primarily on behavioral aspects. Although the social and economic values pursued by social enterprises are important virtues for social entrepreneurs, research on the value orientation of social entrepreneurship is insufficient. The essence of a social enterprise is creating social value based on financial sustainability, so the concept of blended value has been recently emphasized. This study analyzed the relationships among blended value orientation, social entrepreneurship, and the performance of social enterprises. The results indicate that the blended value orientation of social entrepreneurs influenced social entrepreneurship and performance; social entrepreneurship fully mediated blended value orientation and performance. These findings suggest that it is important to focus on the blended value orientation of social entrepreneurs and social entrepreneurship in the promotion and policies of social enterprises