Article
Chemistry, Physical
Lihong Huang, Jiansong Liao, Guocai Yuan, Tong Liu, Xiaobo Lei, Chao Wang, Qinyong Zhang
Summary: P-type Mg3Sb2-based Zintl compounds have been less explored due to their lower ZT values compared to n-type compounds. In this work, Ge doping on the Bi site of Mg3Sb1.5Bi0.5 is performed, resulting in improved carrier mobility and electrical conductivity, as well as reduced lattice thermal conductivity. A maximum ZT value of 0.5 is achieved at 723 K in Mg3Sb1.5Bi0.47Ge0.03 with a carrier concentration of 5.02 x 10(19)/cm(3).
MATERIALS TODAY ENERGY
(2022)
Article
Physics, Multidisciplinary
Yan He, Hua-Kai Xu, Gang Ouyang
Summary: The transport properties of core-shell nanowires under interface modulation and confinement are investigated in this study. It is found that interface modulation can optimize the band alignment, reduce the lattice mismatch, and enhance the carrier mobility. The underlying mechanism regarding the interface shape dependence of transport properties in core-shell nanowires is clarified. This research reveals the potential of interface modulation in improving the performance of nanoelectronic devices.
Article
Nanoscience & Nanotechnology
A. Cros, A. Garcia Cristobal, K. Hestroffer, B. Daudin, J. Wang, F. Demangeot, R. Pechou
Summary: Analysis of electron-phonon coupling in GaN/AlN core-shell nanowires using Raman scattering excited at various UV wavelengths revealed different vibration modes of phonons under different excitations. The thickness of the AlN shell can be adjusted to tune the energy and character of the electronic bands in these nanowires.
Article
Chemistry, Physical
Yuki Okigawa, Tomoaki Masuzawa, Kenji Watanabe, Takashi Taniguchi, Takatoshi Yamada
Summary: The temperature dependence of electrical properties of CVD graphene on HPHT h-BN was evaluated, showing that carrier mobility is influenced by the thickness of HPHT h-BN and can be suppressed by increasing the thickness to mitigate Coulomb scattering. Phonon scattering of graphene and h-BN were found to limit carrier mobility at different temperatures, resulting in different electrical properties.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Ceramics
Thi Ha Tran, Thi Mai Anh Nguyen, Vu Phuong Thao Dao, Cong Doanh Sai, Thanh Cong Bach, Nguyen Hai Pham, An Bang Ngac, Van Thanh Pham, Thi Kim Chi Tran, Hyeonsik Cheong, Viet Tuyen Nguyen
Summary: This study reports a facile process to fabricate CuO/Au core/shell nanowires, which show high sensitivity as SERS substrates capable of detecting methylene blue at concentrations as low as 10(-13) M. The major advantages of these SERS substrates are their sensitivity, uniformity, and purity without the presence of organic surfactants in the synthesis process.
CERAMICS INTERNATIONAL
(2022)
Article
Nanoscience & Nanotechnology
Kazi M. Alam, Charles E. Jensen, Pawan Kumar, Riley W. Hooper, Guy M. Bernard, Aakash Patidar, Ajay P. Manuel, Naaman Amer, Anders Palmgren, David N. Purschke, Narendra Chaulagain, John Garcia, Phillip S. Kirwin, Lian C. T. Shoute, Kai Cui, Sergey Gusarov, Alexander E. Kobryn, Vladimir K. Michaelis, Frank A. Hegmann, Karthik Shankar
Summary: A potential solution to the extraction of photogenerated holes from CdS nanocrystals and nanowires was presented by constructing CdS-C3N5 heterostructures, which improved photocatalytic degradation and photocatalytic decolorization performance while providing control over the reaction pathways.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
K. P. Mithun, Shalini Tripathi, Ahin Roy, N. Ravishankar, A. K. Sood
Summary: We investigated carrier relaxation dynamics in semiconducting tellurium nanowires using ultrafast time-resolved terahertz spectroscopy. The relaxation process was found to exhibit bi-exponential decay with two time scales depending on the amount of capping agent on the TeNWs surface. A coupled rate equation model was used to quantitatively understand the relaxation mechanisms and the observed temperature-dependent dynamics. Furthermore, the frequency-dependent THz photoconductivity was modeled using the Boltzmann transport equation, revealing the contributions of short range and Coulomb scattering rates in the relaxation process.
Article
Engineering, Electrical & Electronic
Ajay P. Manuel, Saralyn Riddell, Harshitha Rajashekhar, Damini Vrushabendrakumar, Kazi M. Alam, Pawan Kumar, Sergey Gusarov, Alexander E. Kobryn, Mustafa Supur, Richard L. McCreery, Karthik Shankar
Summary: Core-shell Au@Pt nanoislands were fabricated on glass substrates using magnetron sputtering and thermal annealing. Addition of ultrathin Pt shells caused redshift and broadening of the localized surface plasmon resonance peak of Au. The coated Au@Pt nanoislands showed superior methylene blue degradation performance and hot carrier injection was validated by Raman thermometry studies.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Physics, Applied
S. Majdi, V. Djurberg, M. Asad, A. Aitkulova, N. Suntornwipat, J. Stake, J. Isberg
Summary: In this study, the researchers successfully fabricated graphene-diamond heterostructures by transferring graphene to an ultra-pure single-crystalline diamond substrate. Hall-effect measurements were conducted to investigate the charge transport properties in these devices. Enhanced hole mobility of 2750 cm(2) V-1 s(-1) was observed at room temperature when using diamond with reduced nitrogen impurity concentration, and the upper limit for mobility was determined by electrostatically varying the carrier concentration. These results are promising for enabling room-temperature applications of carbon-carbon devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Runzhang Xie, Qing Li, Peng Wang, Xiaoshuang Chen, Wei Lu, Huijun Guo, Lu Chen, Weida Hu
Summary: This paper presents an analytic theory of avalanche based on quantum mechanics for a narrow-band material HgCdTe, avoiding fitting parameters and statistical estimations, and proposing a full spatial description of the avalanche. By utilizing probability density functions and history-dependent theory, the impact of carrier generation characteristics on the avalanche process is demonstrated.
Article
Chemistry, Multidisciplinary
Kanishka Kobbekaduwa, Exian Liu, Qian Zhao, Jasjit Singh Bains, Jianbing Zhang, Ying Shi, Haimei Zheng, Dawen Li, Tong Cai, Ou Chen, Apparao M. Rao, Matthew C. Beard, Joseph M. Luther, Jianbo Gao
Summary: We investigated the carrier drift dynamics in CsPbI3 nanocrystal thin films with a time resolution of sub 25 ps. The carriers exhibit band-like transport characteristics similar to traditional semiconductor solar absorbers (Si and GaAs) due to optical phonon and carrier scattering at high temperatures, prior to trapping. In contrast to popular polaron scattering mechanism, CsPbI3 nanocrystal thin film demonstrates the strongest optical phonon scattering mechanism among other inorganic-organic hybrid perovskites, Si, and GaAs. This ultrafast dynamics study provides a foundation for understanding the fundamental carrier drift properties in perovskite nanocrystal optoelectronics.
Article
Nanoscience & Nanotechnology
Xuejing Wang, Yung-Chen Lin, Chia-Tse Tai, Seok Woo Lee, Tzu-Ming Lu, Sun Hae Ra Shin, Sadhvikas J. Addamane, Chris Sheehan, Jiun-Yun Li, Yerim Kim, Jinkyoung Yoo
Summary: In this study, we report the growth of a SiGe(P)/Si core/shell nanowire heterostructure using chemical vapor deposition and vapor-liquid-solid growth mechanism. The entire heterostructure behaves as a p-type semiconductor, with high-density carriers confined within the Si shell forming a tubular conduction channel. These findings are confirmed by calculations and the analysis of current-voltage characteristics. The microscopic analysis reveals a coherent epitaxial core/shell interface, with strain being released through the formation of dislocations along the axial direction of the heterostructure.
Article
Optics
Matthias M. Wiecha, Rohit Kapoor, Hartmut G. Roskos
Summary: In this study, a terahertz scattering-type scanning near-field optical microscope was used for nano-scale non-invasive conductivity measurements on bulk silicon samples. The research investigated the density of charge carriers determined by optical interband excitation and extended to impurity-doped silicon samples. The technique proposed in this study shows promise for spatially resolved quantitative characterization of micro- and nanoelectronic materials and devices through measurements of near-field signal phase.
Article
Chemistry, Multidisciplinary
Tatsuki Hinamoto, Yea-Shine Lee, Sina Abedini Dereshgi, Jennifer G. DiStefano, Roberto dos Reis, Hiroshi Sugimoto, Koray Aydin, Minoru Fujii, Vinayak P. Dravid
Summary: Heterostructures of transition metal dichalcogenides and optical cavities have great potential in quantum optics and electronics. In this study, Si@MoS2 core-shells were synthesized and MD mode splitting was experimentally demonstrated, showing evidence for resonance coupling. Additionally, higher-order systems with tunable properties were demonstrated through a dimer system of Si@MoS2.
Article
Chemistry, Multidisciplinary
Shijia Zeng, Zhenbo Li, Wenjiang Tan, Jinhai Si, Yuren Li, Xun Hou
Summary: This study compares the ultrafast carrier dynamics in InP/ZnSe/ZnS core/shell/shell quantum dots (CSS-QDs) and InP/ZnS core/shell QDs (CS-QDs), revealing the impact of the ZnSe midshell on carrier dynamics. The results show that the ZnSe midshell enhances electron delocalization, prolongs the in-band relaxation time of electrons and holes, and reduces defect emissions. Additionally, the ZnSe midshell leads to an increased density of higher-energy hole states, which may decrease the probability of Auger recombination.
Article
Chemistry, Multidisciplinary
Minju Kim, Han-gyu Kim, Soohyung Park, Jin Sung Kim, Hyoung Joon Choi, Seongil Im, Hyunbok Lee, Taekyeong Kim, Yeonjin Yi
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2019)
Article
Physics, Multidisciplinary
Young Woo Choi, Hyoung Joon Choi
PHYSICAL REVIEW LETTERS
(2019)
Article
Physics, Applied
Eunjung Ko, Kai Liu, Cheol Seong Hwang, Hyoung Joon Choi, Jung-Hae Choi
PHYSICAL REVIEW APPLIED
(2019)
Article
Spectroscopy
Thi Huyen Nguyen, Thi Minh Hien Nguyen, Boyoun Kang, Beongki Cho, Mancheon Han, Hyoung Joon Choi, Mihye Kong, Yongjae Lee, In-Sang Yang
JOURNAL OF RAMAN SPECTROSCOPY
(2019)
Article
Chemistry, Multidisciplinary
Han Sol Lee, Sam Park, June Yeong Lim, Sanghyuck Yu, Jongtae Ahn, Do Kyung Hwang, Yumin Sim, Je-Ho Lee, Maeng-Je Seong, Sehoon Oh, Hyoung Joon Choi, Seongil Im
Article
Materials Science, Multidisciplinary
Young Woo Choi, Hyoung Joon Choi
Summary: The study reveals that the interband tunneling properties in lateral black phosphorus junctions are significantly influenced by the anisotropic pseudospin structure, with different tunneling behaviors observed for different junction directions. Junctions of band-gap inverted BP exhibit variations in tunneling effects based on junction direction, suggesting potential in developing high-performance devices.
Article
Physics, Multidisciplinary
Young Woo Choi, Hyoung Joon Choi
Summary: Graphene moire superlattices exhibit varying electron-phonon coupling strengths in different flat bands, showcasing a correlation between strong electron-phonon coupling and observed robust superconductivity. The presence of sublattice polarization in certain moire flat bands may suppress intersublattice electron-phonon matrix elements, potentially leading to weaker or absent superconductivity. Nonadiabatic superconducting transition temperatures T-c obtained from calculations are in good agreement with experimental results.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Jangwon Kim, Youjin Lee, Young Woo Choi, Taek Sun Jung, Suhan Son, Jonghyeon Kim, Hyoung Joon Choi, Je-Geun Park, Jae Hoon Kim
Summary: We conducted a terahertz spectroscopic study and density functional theory analysis on Nb3Cl8 and Nb3I8, two van der Waals semiconductors. The observed infrared-active phonon modes in the terahertz region matched well with our calculations. We found that the phonon spectra of Nb3Cl8 were consistent with a structural transition at 90 K, while Nb3I8 showed no significant temperature or magnetic field dependence in the phonon spectra. Our study establishes a connection between structural properties and paramagnetic-nonmagnetic transitions in these compounds.
Article
Materials Science, Multidisciplinary
Mancheon Han, Hyoung Joon Choi
Summary: We have developed a reliable parameter-free analytic continuation method for quantum many-body calculations. The method utilizes a kernel grid, a causal spline, a regularization approach, and the L-curve criterion. Additionally, we have introduced the L-curve averaged deviation to estimate the precision of our analytic continuation. To handle statistically obtained data more efficiently, we have also developed a bootstrap-averaged analytic continuation method. The results demonstrate the effectiveness of our method in converging to the exact spectral function when applied to imaginary-frequency Green's function with added statistical error. Furthermore, we have successfully identified a non-Fermi-liquid behavior in the two-orbital Hubbard model using our analytic continuation method. This research significantly contributes to improving the accuracy and clarity of conclusions drawn from imaginary-time quantum many-body calculations.
Article
Materials Science, Multidisciplinary
Mancheon Han, Hyoung Joon Choi
Summary: Researchers develop a causal optimization method to ensure causality in numerical calculations of Green's functions in interacting electron systems. They find that intermediate-frequency behaviors of Green's functions are determined solely by causality, and their method provides a basis for improving stability and efficiency of numerical simulations of quantum many-body systems.
Article
Materials Science, Multidisciplinary
Han-gyu Kim, Hyoung Joon Choi
Summary: We studied the quasiparticle band structures, spontaneous polarization, and spin-splitting in noncentrosymmetric gamma-GeSe, finding it to possess semiconductor properties with spontaneous polarization resulting from small charge transfer between layers, and more significant spin-splitting in the valence band.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Han-gyu Kim, Hyoung Joon Choi
Summary: First-principles density functional theory (DFT) and GW calculations were used to investigate the electronic structures of bulk and few-layer PdSe2. The obtained quasiparticle band structures and electronic structure parameters provide a foundation for both basic research and device applications.
Article
Materials Science, Multidisciplinary
Han-gyu Kim, Hyoung Joon Choi
Summary: This study accurately determines the work function, ionization energy, and electron affinity of few-layer and bulk MX2 through density functional theory and GW calculations, analyzing the impact of thickness on these properties and discussing the band alignment types of these compounds.
Article
Materials Science, Multidisciplinary
Young Woo Choi, Hyoung Joon Choi
Article
Materials Science, Multidisciplinary
Sehoon Oh, June Yeong Lim, Seongil Im, Hyoung Joon Choi
