미중 반도체 갈등과 중국의 대응 전략 분석 – 미국의 대중 반도체 제재 딜레마와 중국의 3가지 돌파구를 중심으로 –

남은영 중국지역학회 2023 중국지역연구 Vol.10 No.4

This study conducts an in-depth analysis of China's response strategy based on the semiconductor sanctions dilemma imposed by the United States on China. While the United States is strengthening sanctions to decouple from China in the advanced semiconductor field, it is also tolerating coupling with China in the general semiconductor market, fearing infringement on the interests of U.S. companies. This dilemma faced by the United States presents both opportunities and challenges for China. China perceives the U.S. tolerance for coupling as an opportunity and is reinforcing the development of the general semiconductor industry. China's promotion of the general semiconductor industry, which is larger in scale than advanced semiconductors, can contribute to China gaining an advantage in the general semiconductor market. Simultaneously, it provides an opportunity to leverage outdated semiconductor technology, for the development of advanced performance semiconductors. In the short term, China employs a bypass strategy actively utilizing outdated technology for semiconductor industry self-sufficiency. Concurrently, China is responding to U.S. high tech restrictions by pursuing a medium-to-long-term strategy involving talent development and the development of third-generation semiconductors. The U.S. focus on decoupling from Chinese semiconductors aligns with advanced technologies, shaping its response accordingly. The U.S. strategy, driven by security concerns originating from China and the values of alliances, aims to reshape the global supply chain in the semiconductor industry. This has led to diverse analyses connected to international political theories such as power politics, diplomatic security, and more. However, this framework makes it challenging to explain the U.S. dilemma of allowing coupling with China in outdated semiconductor technology to benefit the interests of the U.S. semiconductor industry. The U.S. semiconductor containment against China appears to be more a part of a significant industrial policy for fostering the semiconductor industry than a practical outcome of U.S. diplomatic and security strategies. This U.S. approach and China's response provide three implications for the development direction of the South Korean semiconductor industry: expanding South Korean companies' general semiconductor business in China, maintaining relationships that can collaborate on the establishment of third-generation semiconductor standards expected to be widely adopted in China, especially in power semiconductors, and strengthening semiconductor talent collaboration between South Korea and both the United States and China.

Design of visible-light photocatalysts by coupling of inorganic semiconductors

Bera, Sandipan,Won, Dong-Il,Rawal, Sher Bahadur,Kang, Hye Jin,Lee, Wan In Elsevier 2019 CATALYSIS TODAY - Vol.335 No.-

<P><B>Abstract</B></P> <P>The design of advanced photocatalytic systems, effectively working under visible-light, is essential for practical application of photocatalysts in removing environmental pollutants. To achieve high efficiency, the required properties for the photocatalysts are profound solar light absorption in the visible-range, efficient charge-separation, suitable energy band locations for redox reactions, and extended photostability. As a single semiconductor-based photocatalyst cannot satisfy all of these requirements, a potential strategy will be construction of coupled structures between two or more semiconductors. In the present study, we explore various types of photocatalytic systems constructed by coupling semiconductors and their working mechanisms. When two narrow bandgap semiconductors (NBSs) absorbing visible-light are coupled to form heterojunction structures, they can be classified as <I>p-n</I> junction or Z-scheme systems, according to the charge-flow pathway between the two semiconductors. When a NBS that absorbs visible-light is coupled with a wide bandgap semiconductor (WBS) functioning as the main photocatalyst, the fabricated catalytic systems can be classified as Type-A or Type-B heterojunction systems dependent on their relative energy band locations. Herein various semiconductor composites reported to be visible-light photocatalysts in the literature are classified using these categories, and their photocatalytic mechanisms, including charge-flow pathways, are discussed in depth. In addition, recent progress and future perspectives for heterojunction systems are reviewed and discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Various visible-light photocatalysts can be designed by coupling of semiconductors. </LI> <LI> Photocatalytic systems were classified as p-n junction, Z-scheme, Type-A and Type-B. </LI> <LI> Design concept and working mechanism for each catalytic system were handled in depth. </LI> <LI> Individual example and perspective for each heterostructure were described intimately. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ambipolar Small-Molecule:Polymer Blend Semiconductors for Solution-Processable Organic Field-Effect Transistors

Kang, Minji,Hwang, Hansu,Park, Won-Tae,Khim, Dongyoon,Yeo, Jun-Seok,Kim, Yunseul,Kim, Yeon-Ju,Noh, Yong-Young,Kim, Dong-Yu American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.3

<P>We report on the fabrication of an organic thin-film semiconductor formed using a blend solution of soluble ambipolar small molecules and an insulating polymer binder that exhibits vertical phase separation and uniform film formation. The semiconductor thin films are produced in a single step from a mixture containing a small molecular semiconductor, namely, quinoidal biselenophene (QBS), and a binder polymer, namely, poly(2-vinylnaphthalene) (PVN). Organic field-effect transistors (OFETs) based on QBS/PVN blend semiconductor are then assembled using top-gate/bottom-contact device configuration, which achieve almost four times higher mobility than the neat QBS semiconductor. Depth profile via secondary ion mass spectrometry and atomic force microscopy images indicate that the QBS domains in the films made from the blend are evenly distributed with a smooth morphology at the bottom of the PVN layer. Bias stress test and variable-temperature measurements on QBS-based OFETs reveal that the QBS/PVN blend semiconductor remarkably reduces the number of trap sites at the gate dielectric/semiconductor interface and the activation energy in the transistor channel. This work provides a one-step solution processing technique, which makes use of soluble ambipolar small molecules to form a thin-film semiconductor for application in high-performance OFETs.</P>

Strategies to Reduce Transient Liquid Phase Bonding Time for the Die Attach of Power Semiconductors

Sunghyun Sohn,Daewon Kim,Hongpyo Kim,Namhyun Kang 대한용접·접합학회 2020 대한용접·접합학회지 Vol.38 No.2

Wide band gap (WBG) power semiconductors have superior properties and accordingly demand for WBG semiconductors has grown recently in various fields, including national defense applications. Since WBG power semiconductors operate in high temperature conditions, interconnects with high temperature reliability are required. Transient liquid phase bonding (TLPB) is emerging as one of the die attach technologies for WBG power semiconductors. However, TLPB has drawbacks, such as long bonding times and void formation. We investigated various methods to address the shortcomings of TLPB, and determined TLPB time can be reduced and void formation can be suppressed through the development of process and interlayer design. This study describes the principles, strengths and weaknesses of each process and interlayer material design.

Controlled ambipolar charge transport of polymer semiconductors by viologen-doping for complementary-like electronic circuits

Lee, Dong-Hyeon,Yang, Dongseong,Kim, Dong-Yu,Baeg, Kang-Jun Elsevier 2018 Organic electronics Vol.59 No.-

<P><B>Abstract</B></P> <P>We report on controllable ambipolar charge transport in polymeric semiconductors by the incorporation of viologen-based molecular additives. The viologen dopants selectively contribute to an increase in the charge carrier density of the electrons while enhancing the fibril-like crystalline thin-film morphology of the polymers to provide favourable charge transport in staggered-structure organic field-effect transistors. A well-balanced ambipolar behaviour is obtained at the optimised viologen concentration in donor-acceptor conjugated polymers by conversely modulating the <I>p</I>- and <I>n</I>-channel carrier mobilities within a given active layer. Complementary-like inverter circuits are demonstrated through the application of a simple blanket coating of a viologen-doped ambipolar semiconductor, which exhibits high ideal voltage switching at around half of the applied bias, a high gain of more than 50, and sufficient noise immunity to enable various applications for printed electronics and optoelectronics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Controllable ambipolar charge transport in ambipolar polymer semiconductors. </LI> <LI> Selective contribution to an increase in the electron carrier density. </LI> <LI> Enhancement of the fibril-like crystalline thin-film morphology. </LI> <LI> A well-balanced ambipolar behaviour at the optimised viologen doping concentration. </LI> <LI> CMOS-like inverters by a simple blanket coating of N-doped ambipolar semiconductor. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Controllable ambipolar charge transport in ambipolar polymer semiconductors by the incorporation of benzyl viologen-based molecular additives for applications to complementary-like solution-processed electronic circuits.</P> <P>[DISPLAY OMISSION]</P>

Semiconductor Nanoparticles with Surface Passivation and Surface Plasmon

Dae-Ryong Jung,Jongmin Kim,남창우,Hongsik Choi,Seunghoon Nam,Byungwoo Park 대한금속·재료학회 2011 ELECTRONIC MATERIALS LETTERS Vol.7 No.3

Semiconductor nanoparticles have recently attracted a significant amount of attention from the materials science community. Nanoparticles with diameters in the range of 1 nm to 20 nm exhibit unique physical properties that give rise to many potential applications. Two fundamental factors are crucial as regards the novel properties of semiconductor nanoparticles. The first is the large surface-to-volume ratio. In this regard, the surface states are likely to trap electrons and/or holes, and induce a nonradiative recombination of these charge carriers,leading to a reduction in the luminescent and photovoltaic efficiency. The second approach takes advantage of the surface-plasmon resonance from metal nanostructures to semiconductors. The interactions between the semiconductor nanoparticles and the surface plasmons generate enhanced emission by electromagnetic-field amplification, and also causes the suppression of the emission by the energy transfer between the semiconductor and the metal nanoparticles. Therefore, surface passivation and surface plasmon in semiconductor nanoparticles with controlled nanostructures are important when attempting to improve both the luminescent and photovoltaic efficiency.

High-Mobility Pyrene-Based Semiconductor for Organic Thin-Film Transistors

Cho, Hyunduck,Lee, Sunyoung,Cho, Nam Sung,Jabbour, Ghassan E.,Kwak, Jeonghun,Hwang, Do-Hoon,Lee, Changhee American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.9

<P>Numerous conjugated oligoacenes and polythiophenes are being heavily studied in the search for high-mobility organic semiconductors. Although many researchers have designed fused aromatic compounds as organic semiconductors for organic thin-film transistors (OTFTs), pyrene-based organic semiconductors with high mobilities and on–off current ratios have not yet been reported. Here, we introduce a new pyrene-based p-type organic semiconductor showing liquid crystal behavior. The thin film characteristics of this material are investigated by varying the substrate temperature during the deposition and the gate dielectric condition using the surface modification with a self-assembled monolayer, and systematically studied in correlation with the performances of transistor devices with this compound. OTFT fabricated under the optimum deposition conditions of this compound, namely, 1,6-bis(5′-octyl-2,2′-bithiophen-5-yl)pyrene (BOBTP) shows a high-performance transistor behavior with a field-effect mobility of 2.1 cm<SUP>2</SUP> V<SUP>–1</SUP> s<SUP>–1</SUP> and an on–off current ratio of 7.6 × 10<SUP>6</SUP> and enhanced long-term stability compared to the pentacene thin-film transistor.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-9/am4005368/production/images/medium/am-2013-005368_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am4005368'>ACS Electronic Supporting Info</A></P>

Solution-processed ambipolar polymer semiconductor films for high-performance complementary-like printed and flexible electronic circuits

Lee Jeong Min,Jung Ji-Yoon,Baeg Kang-Jun 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.5

In polymer semiconductor flms, charge transport primarily occurs along the conjugated backbone, making the alignment of polymer chains crucial for superior electrical performance. This study focused on the fabrication of high-mobility organic feld-efect transistors (OFETs) based on an ambipolar polymer semiconductor. Using simple directional solution processes, specifcally of-center spin coating and bar-coating techniques, we successfully fabricated complementary-like inverter circuits. These OFETs, compared to their counterparts produced via conventional on-center spin coating, demonstrated enhanced ambipolar behavior and exhibited a heightened feld-efect mobility of up to 4 cm2 /Vs. Furthermore, by optimizing bar-coating conditions to achieve optimal alignment of the polymer chains, we developed a complementary-like inverter with a single-component active layer, demonstrating well-balanced p-channel and n-channel characteristics. The inverter showed an almost ideal switching point at half the supplied bias, with an impressive gain exceeding 30. Conventional organic semiconductors often encounter challenges, such as limited charge mobilities and suboptimal electrical performance. However, by implementing methods that optimize the alignment of polymer semiconductors, these limitations can be surpassed, thereby enhancing overall device characteristics. This allows for the realization of high-performance and economically viable printed and fexible electronic devices.

Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

Ali Mirzaei,Jeung-SooHuh,김상섭,김현우 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.3

Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenictemperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperaturedue to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficientroom temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland securityapplications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detectionis broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most importantmaterials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternarychalcogenide compounds.

Solution-processable end-functionalized tetrathienoacene semiconductors: Synthesis, characterization and organic field effect transistors applications

Mamillapalli, Narendra Chary,Vegiraju, Sureshraju,Priyanka, Pragya,Lin, Chih-Yu,Luo, Xian-Lun,Tsai, Hsiang-Chi,Hong, Shao-Huan,Ni, Jen-Shyang,Lien, Wei-Chieh,Kwon, Guhyun,Yau, Shueh Lin,Kim, Choongik Applied Science Publishers 2017 Dyes and pigments Vol.145 No.-

<P><B>Abstract</B></P> <P>A series of dialkylated tetrathienoacene (<B>TTAR</B>)-based solution-processable small molecular organic semiconductors have been synthesized and characterized for organic field effect transistor (OFET) applications. The central dialkylated <B>TTAR</B> moiety was end-capped with thiophenylvinylthiophene (<B>TVT</B>), bithiophene (<B>bT</B>), and thienothiophene (<B>TT</B>) to afford new π-conjugated p-type active materials, <B>DTVT-TTAR</B> (<B>1</B>), <B>DbT-TTAR</B> (<B>2</B>), and <B>DTT-TTAR</B> (<B>3</B>), respectively. The physical and electrochemical properties and theoretical calculations as well as OFETs performance and thin film morphologies and microstructures of these new soluble <B>TTAR</B>s are systematically studied. Using a solution-shearing method, <B>DTVT-TTAR</B> exhibits p-channel transport with the highest mobility of up to 0.18 cm<SUP>2</SUP> V<SUP>−1</SUP>s<SUP>−1</SUP> and current ON/OFF ratios of 10<SUP>4</SUP>-10<SUP>6</SUP>, which is one of the highest hole mobilities for the solution-processed <B>TTAR</B>-based small molecules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis and characterization of dialkylated tetrathienoacene derivatives as semiconductors. </LI> <LI> Various substituents as end groups for solution-processed p-type semiconductors. </LI> <LI> P-type transport with highest mobility up to 0.18 cm<SUP>2</SUP> V<SUP>−1</SUP>s<SUP>−1</SUP>. </LI> <LI> One of the highest mobilities for dialkylated tetratheinoacene derivaties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>