Article
Chemistry, Multidisciplinary
Thomas Kanne, Dags Olsteins, Mikelis Marnauza, Alexandros Vekris, Juan Carlos Estrada Saldana, Sara Loric, Rasmus D. Schlosser, Daniel Ross, Szabolcs Csonka, Kasper Grove-Rasmussen, Jesper Nygard
Summary: The core platform of several recent quantum device proposals relies on parallel 1D semiconductor channels connected by a superconducting strip, utilizing Andreev processes or topological effects. A strategy for synthesizing double InAs nanowires using III-V molecular beam epitaxy is presented, allowing for the deposition of a superconducting layer onto nanowires without breaking the vacuum in order to ensure pristine interfaces between the superconductor and the semiconductor nanowires. The method demonstrates the utility of high yield merged or separate parallel nanowires with full or half-shell superconductor coatings in complex quantum devices through electron transport measurements.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Review
Chemistry, Multidisciplinary
Cosimo Anichini, Paolo Samori
Summary: Graphene, a 2D material with outstanding physical properties, can be combined with other nanomaterials or molecules to form hybrid functional materials, showcasing new properties and enhanced characteristics. These hybrids exhibit superior performances compared to individual components in various technological applications, such as sensing, water purification, energy storage, biomedical applications, catalysis, and optoelectronics.
Review
Chemistry, Multidisciplinary
Jinhong Du, Bo Tong, Shuangdeng Yuan, Nian Dai, Rui Liu, Dingdong Zhang, Hui-Ming Cheng, Wencai Ren
Summary: This article reviews the recent advances and significant development of CVD-grown graphene towards flexible optoelectronics. The challenges of improving optoelectronic properties, tuning work functions, and controlling interfaces are discussed, and the importance of fabricating large-area devices on flexible substrates is emphasized.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Nguyen Ngan Nguyen, Hyo Chan Lee, Kangkyun Baek, Min Seok Yoo, Hansol Lee, Hyungsub Lim, Shinyoung Choi, Cheol-Joo Kim, SungWoo Nam, Kilwon Cho
Summary: The hybrid graphene template enables the preparation of highly crystalline organic semiconductor thin films with large grain sizes. Compared to conventional graphene templates, phototransistors fabricated on this hybrid template exhibit significantly higher photoresponsivity.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Manuel Vazquez Sulleiro, Aysegul Develioglu, Ramiro Quiros-Ovies, Lucia Martin-Perez, Natalia Martin Sabanes, Maria Lourdes Gonzalez-Juarez, I. Jennifer Gomez, Mariano Vera-Hidalgo, Victor Sebastian, Jesus Santamaria, Enrique Burzuri, Emilio M. Perez
Summary: The research successfully achieved the coupling of 2H-MoS2 and graphene in field-effect transistors through covalent grafting, providing the possibility of functionalizing multiple devices.
Article
Chemistry, Multidisciplinary
Mirela Petruta Suchea, Evangelia Petromichelaki, Cosmin Romanitan, Maria Androulidaki, Alexandra Manousaki, Zacharias Viskadourakis, Rabia Ikram, Petronela Pascariu, George Kenanakis
Summary: This study examined the use of common beverages as reagents for synthesizing ZnO coatings in place of expensive high purity reagents, resulting in nanostructured ZnO coatings with good optical properties. The research provides insights into the surface structuring of ZnO coatings and the potential for utilizing non-toxic beverages in optoelectronic applications.
Article
Chemistry, Multidisciplinary
Bilal Kousar, Damon J. Carrad, Lukas Stampfer, Peter Krogstrup, Jesper Nygard, Thomas S. Jespersen
Summary: In this study, the performance of devices consisting of InAs nanowires in electrical contact with MoRe superconducting alloys was investigated. The MoRe thin films exhibited high transition temperatures and critical magnetic fields, and the devices maintained superconductivity at temperatures up to around 10 K. The MoRe-based Josephson devices showed supercurrents and multiple Andreev reflections. Additionally, the induced superconducting gap was found to be lower than expected and exhibited gap softening at finite magnetic fields.
Article
Chemistry, Multidisciplinary
Minh Nhut Le, Kang-Jun Baeg, Kyung-Tae Kim, Seung-Han Kang, Byung Doo Choi, Chan-Yong Park, Seong-Pil Jeon, Sol Lee, Jeong-Wan Jo, Seonhyoung Kim, Jun-Gu Park, Dongil Ho, Jongin Hong, Miso Kim, Han-Ki Kim, Choongik Kim, Kwanpyo Kim, Yong-Hoon Kim, Sung Kyu Park, Myung-Gil Kim
Summary: Stress-diffusive organic-inorganic hybrid superlattice nanostructures have been developed to overcome the mechanical limitations of metal oxides in flexible electronic applications, providing high electrical conductivity and mechanical stability.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Shuichi Toyouchi, Mathias Wolf, Guilin Feng, Yasuhiko Fujita, Beatrice Fortuni, Tomoko Inose, Kenji Hirai, Steven De Feyter, Hiroshi Uji-I
Summary: We present a facile all-optical method for spatially resolved and reversible chemical modification of a graphene monolayer. By using a tightly focused laser under water, sp(3)-type chemical defects can be introduced by photo-oxidation, and then reversibly restored to sp(2) carbon centers by a higher intensity laser through photoreduction induced by local heating. These optical methods, combined with laser direct writing technique, allow photowriting and erasing of well-defined chemical patterns on graphene with a spatial resolution of about 300 nm. The pattern can be visualized and optically read out by Raman mapping with the same excitation laser. We demonstrate the all-optical Write/Read-out/Erase of chemical functionalization patterns on graphene simply by adjusting the one-color laser intensity. This all-optical method enables flexible and efficient tailoring of physicochemical properties at the nanoscale for future applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Shayan Angizi, Xianxuan Huang, Lea Hong, Md Ali Akbar, P. Ravi Selvaganapathy, Peter Kruse
Summary: In this study, a highly pH-sensitive substrate was fabricated by controlling the type and defect density of graphene derivatives. The pH-sensing mechanisms of graphene were demonstrated using nanomaterials of different graphene structures. The study identified three competing mechanisms of pH sensitivity and investigated the function and density of graphene pH-sensitive functional groups. It opens up a new avenue for integrating micro-nano-sized pH sensors based on graphene derivatives into next-generation sensing platforms.
Article
Chemistry, Multidisciplinary
Demetrios D. Chronopoulos, Christina Stangel, Magdalena Scheibe, Klara Cepe, Nikos Tagmatarchis, Michal Otyepka
Summary: A new material was synthesized by combining fullerene and graphene, which are non-metal covalent hybrids. The material showed excellent electrocatalytic performance and durability for the hydrogen evolution reaction, attributed to intrahybrid charge-transfer phenomena.
CHEMICAL COMMUNICATIONS
(2022)
Article
Green & Sustainable Science & Technology
Dibyendu Ghosh, Krishnendu Sarkar, Pooja Devi, Ki-Hyun Kim, Praveen Kumar
Summary: Carbon quantum dots (CQDs) and graphene quantum dots (GQDs) are novel carbon-based nanomaterials with unique properties that have been widely studied in various fields, but their potential in energy applications is still underexplored. This review focused on the role and challenges of CQDs/GQDs in flexible optoelectronic devices for energy harvesting, discussing their potential and future prospects for industrial scale-up.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Chemistry, Physical
Daria Belotcerkovtceva, J. Panda, M. Ramu, Tapati Sarkar, Ulrich Noumbe, M. Venkata Kamalakar
Summary: Understanding the stability and current-carrying capacity of graphene spintronic devices is crucial for their applications in spin current sensors, spin-torque oscillators, and spin-integrated circuits. In this study, it was found that chemical vapor deposited (CVD) graphene can sustain remarkably high currents of 5.2 x 10(8) A/cm(2), which is two orders higher than previously reported values in multilayer CVD graphene. The current-carrying capacity of CVD graphene primarily depends on its sheet resistance, and it can operate without degradation at high operating currents of 10(8) A/cm(2).
Review
Nanoscience & Nanotechnology
Ziqing Huang, Guanhui Chen, Feilong Deng, Yiming Li
Summary: Graphdiyne, a novel 2D carbon material with unique properties, has shown great potential in various fields such as catalysis, energy storage, and biomedicine.
INTERNATIONAL JOURNAL OF NANOMEDICINE
(2022)
Article
Chemistry, Physical
Ju Hwan Kang, Sukyung Choi, Yu Jung Park, Jin Sung Park, Nam Sung Cho, Shinuk Cho, Bright Walker, Dong Soo Choi, Jin-Wook Shin, Jung Hwa Seo
Summary: Cu/graphene hybrid films serve as both p-type and n-type transparent conducting electrodes in organic solar cells, with sheet resistance and work function being significantly improved by controlling the thickness of Cu. The films also exhibit wrinkle features and doubled RMS currents, while devices utilizing Cu/graphene electrodes show much higher power conversion efficiencies compared to those with pristine graphene electrodes.
Article
Nanoscience & Nanotechnology
Chang-Hyun Kim
Summary: This study provides a comprehensive insight into the phenomenon of ambient doping in organic rectifying diodes (ORDs), revealing its impact on multiple device locations and operating modes. Through detailed analysis, critical charge-injection, transport, and doping parameters are extracted, and a validated circuit model is established.
Article
Chemistry, Multidisciplinary
Seyed Mehdi Sattari-Esfahlan, Yvan Bonnassieux, Ioannis Kymissis, Chang-Hyun Kim
Summary: This study demonstrates a high-performance resistive-switching memory cell based on biomass-derived nanoporous graphene (NPG) materials. A new processing method is used to create 3D NPG from Saccharum officinarum, revealing the oxygen ion migration and charge-injection modulation as the key mechanism.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Energy & Fuels
Hyuna Lee, Aniket Rana, Ioannis Kymissis, Chang-Hyun Kim
Summary: This article provides a new insight into the charge-carrier mobility in perovskite solar cells using experimentally calibrated numerical simulations. It is found that increasing the mobility substantially improves the short-circuit current, but simultaneously decreases the open-circuit voltage, resulting in efficiency roll-off in the high-mobility regime. The increased bending of potential profiles and decreased electric field due to carrier diffusion are identified as the key mechanisms behind this behavior, providing a theoretical guideline for material and device engineering.
Article
Multidisciplinary Sciences
Junhwan Choi, Changhyeon Lee, Chungryeol Lee, Hongkeun Park, Seung Min Lee, Chang-Hyun Kim, Hocheon Yoo, Sung Gap Im
Summary: Researchers have developed a multi-valued logic circuit based on heterojunction transistors, which utilizes nonvolatile floating-gate flash memory to control channel conductance and achieve stable operation of ternary logic inverters. The 3D inverters, fabricated in a vertically stacked form, demonstrate high-density integration and device uniformity. The organic flash memory exhibits long retention characteristics, ensuring long-term stability of the 3D inverters. This study provides valuable insights for achieving high-performance multi-valued logic circuits.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Krunoslav Romanjek, Micael Charbonneau, Chang-Hyun Kim
Summary: This paper applies a robust self-consistent parameter extraction method to study high-performance p-type printed polymer field-effect transistors. Contact resistance and intrinsic channel mobility are simultaneously extracted using an analytically reinforced transmission-line method, allowing for full gate-voltage dependence. The results show a minimum width-normalized contact resistance of 12 kΩcm and a maximum hole mobility of 1.9 cm^2V-1s-1. Additionally, the gate-voltage-dependent mobility is explained within the framework of trap-and-release transport through double-exponential density of states, revealing a low disorder energy of 29 meV near the transport orbital.
FLEXIBLE AND PRINTED ELECTRONICS
(2022)
Article
Physics, Applied
Sun-Woo Jo, Seongjae Cho, Chang-Hyun Kim
Summary: This paper presents a comprehensive numerical analysis of contact resistance in coplanar organic thin-film transistors. The relationship between source/drain electrode thickness and contact resistance is found to be complex and strongly associated with the injection energy barrier. The origin of negative contact resistance in organic transistors with minimal charge-injection barrier is explained. Furthermore, the direct impact of semiconductor charge-carrier mobility on contact resistance is addressed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Hyuna Lee, Yeo Eun Kim, Jisuk Bae, Sungyeop Jung, Radu A. Sporea, Chang-Hyun Kim
Summary: We successfully fabricated high-performance organic source-gated transistors using a critical junction formed between indium-tin oxide and diketopyrrolopyrrole polymer. The partially blocked hole-injection interface offers sufficient drain currents and a strong depletion effect, enabling source pinch-off. Our transistors exhibit outstanding metrics, including an intrinsic gain of 160 V/V, an output resistance of 4.6 G Omega, and a saturation coefficient of 0.2 at 5 V. Drift-diffusion simulation reproduces and rationalizes the experimental data, revealing that the effective contact length is significantly reduced in an interdigitated electrode geometry, leading to low-voltage saturation.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Youngmin Han, Seongjae Kim, Chang-Hyun Kim, Hocheon Yoo
Summary: In this study, the effect of a small molecule contact charge injection layer on thin-film transistors (TFTs) was investigated through experimental results and theoretical calculations. It was found that inserting dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) as a charge injection layer can improve the limited electrical characteristics of C8-BTBT TFT. The results of energy structural simulations confirmed the improved contact properties through the DNTT charge injection layer. Furthermore, the effect of the DNTT charge injection layer on the circuit level was verified through improved noise margin characteristics in a complementary inverter.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Hayoung Kim, Amos A. Boampong, Chang-Hyun Kim, Min-Hoi Kim
Summary: This study demonstrates an effective electrical erasing operation in charge-trap memory (CTM) based on wide bandgap (WBG) semiconductors by introducing an electric flux-modulating counter electrode. The limitations of gate-bias erasing operation in WBG CTMs are overcome by utilizing a top Al metal electrode on the bottom-gate top-contact thin-film transistor memories. The proposed concept of electric flux-modulating counter electrode improves the applicability of WBG semiconductors in future memory technologies.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Multidisciplinary
Saurabh Sureda Joshi, Kyung-Geun Lim, Chang-Hyun Kim
Summary: This article proposes a new analytical description method for the current-voltage characteristics of vertical OPBTs. The functional model, based on a geometrical parametrization scheme and an equivalent-circuit approach, provides decoupling of the field effect and bulk charge-transport properties. Experimental data validation and predictive capabilities of the model are demonstrated, making it a practical tool for designing and optimizing next-generation OPBTs.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Youngmin Han, Chang-Hyun Kim, Hocheon Yoo
Summary: In this study, the charge transport behavior in a heterojunction bi-channel composed of two small-molecule p-type-to-p-type semiconductors was investigated. The study found that the channel length had an impact on the characteristics of the bi-channel transistor, and different source operating electrodes affected the threshold voltage and mobility. In addition, the temperature dependence and light-responsivity of the transistor were analyzed, and finite element simulation was used to verify the experimental results.
ORGANIC ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Joon Hyung Park, Ye Ji Shin, Ioannis Kymissis, Yongmin Jeon, Chang-Hyun Kim
Summary: We show the frequency-triggered internal circuit transition in high-performance organic light-emitting diodes. Blue fluorescent light-emitting devices are made using a stable and efficient host-dopant material system. Broad-band impedance spectroscopy analysis reveals two abrupt spectral transitions occurring at two small-signal frequency ranges in these diodes. By fitting Nyquist plots recorded under a wide range of conditions to an equivalent circuit model, we identify the key interface and bulk parameters. The sharp increases in conductance identified from this analysis are conceptually linked to trap deactivation at specific cut-off frequencies, suggesting possibilities for AC applications of organic light-emitting diodes.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Hyuna Lee, Kyung-Geun Lim, Chang-Hyun Kim
Summary: Vertical transistors are essential for future electronics with high density, low power, and high speed. However, there is limited understanding of these unconventional devices, leading to a lack of design rules. This article explores the physical and electrical mechanisms of vertical organic permeable-base transistors, revealing their unique structural features and shedding light on the origin of base-induced current saturation. Predictive simulations based on these insights provide a foundation for theoretically guided materials and device engineering.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Engineering, Electrical & Electronic
Seongjae Kim, Subin Lee, Chang-Hyun Kim, Hocheon Yoo
Summary: This paper proposes the use of a bridge transistor to achieve early saturation characteristics of drain current and investigates the impact of different materials used as bridge layers on the electrical properties of the transistor. The experimental results reveal that bridge transistors with a Schottky junction exhibit early saturation characteristics, which can be attributed to the additional contact resistance and depletion region.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Review
Materials Science, Multidisciplinary
Yutaka Wakayama, Chang-Hyun Kim, Debdatta Panigrahi, Ryoma Hayakawa
Summary: This paper reviews recent progress in antiambipolar transistor (AAT) development, with a focus on the advantages of organic semiconductors (OSCs) as AAT channels and discusses the carrier transport mechanism and AAT applications.
MATERIALS ADVANCES
(2022)