Article
Chemistry, Multidisciplinary
Lance L. McDowell, Jijun Qiu, Milad Rastkar Mirzaei, Binbin Weng, Zhisheng Shi
Summary: The integration of monocrystalline PbSe with vicinal Ge substrate to form a heterogeneous p-n junction structure shows strong p-n heterojunction behavior and potential applications. This is attributed to enhanced surface kinetics influenced by in situ surface treatment of the Ge substrate prior to PbSe deposition. High-quality PbSe(100) films on Ge(100) substrates show promise for photodetector and other heterojunction applications.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Multidisciplinary
Ruiheng Pan, Xiantong Tang, Lixuan Kan, Yang Li, Haomiao Yu, Kai Wang
Summary: This study demonstrates the circular photogalvanic effect (CPGE) and linear photogalvanic effect (LPGE) in (R-MBA)(2)PbI4 and (S-MBA)(2)PbI4 thin film materials. These effects exhibit decent two-fold symmetry for a complete cycle in a wide temperature range from 4 K to 300 K. The effect can be effectively tuned by constant magnetic fields, and the Bychkov-Rashba spin orbit coupling and chiral-induced magnetization are responsible for it. This research shows the promising future of using chiral lead halide perovskites for spin-orbitronics.
Article
Nanoscience & Nanotechnology
Naoki Higashitarumizu, Shiekh Zia Uddin, Daniel Weinberg, Nima Sefidmooye Azar, I. K. M. Reaz Rahman, Vivian Wang, Kenneth B. B. Crozier, Eran Rabani, Ali Javey
Summary: The photophysics of black phosphorus, an optoelectronic material, was investigated. It was found that the photoluminescence quantum yield initially decreases with decreasing thickness due to enhanced surface carrier recombination, but sharply increases afterwards. Furthermore, black phosphorus exhibits a much lower surface carrier recombination velocity compared to other semiconductors.
NATURE NANOTECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Nima Taghipour, Mariona Dalmases, Guy L. Whitworth, Miguel Dosil, Andreas Othonos, Sotirios Christodoulou, Shanti Maria Liga, Gerasimos Konstantatos
Summary: This study utilizes PbS/PbSSe core/alloyed-shell colloidal quantum dots (CQDs) as a gain medium for infrared laser devices. The researchers achieved highly suppressed Auger recombination and lower amplified spontaneous emission (ASE) threshold by doping these engineered CQDs and successfully achieved near-infrared laser emission.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Chang Yan, Daniel Weinberg, Dipti Jasrasaria, Matthew A. Kolaczkowski, Zi-jie Liu, John P. Philbin, Arunima D. Balan, Yi Liu, Adam M. Schwartzberg, Eran Rabani, A. Paul Alivisatos
Summary: Understanding electronic dynamics in multiexcitonic quantum dots is crucial for designing efficient systems in high power scenarios like solar concentrators and multielectron charge transfer. By synthesizing a phenothiazine derivative and using transient absorption spectroscopy, the competition between Auger recombination and hole transfer in CdSe, CdS, and CdSe/CdS QDs was investigated, revealing the beneficial role of hole-trapping states in enhancing hole transfer efficiency under multiexcitonic conditions.
Article
Physics, Applied
Aleksander Afonenko, Dmitry Ushakov, Georgy Alymov, Aleksandr Dubinov, Sergey Morozov, Vladimir Gavrilenko, Dmitry Svintsov
Summary: A semiconductor laser diode based on multiple HgTe quantum wells is proposed to suppress the Auger recombination effect, enabling lasing in the 26-30 μm range at high temperatures up to 90 K with an output power of up to 8 mW in microsecond-duration pulses.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Gerard Michael Carroll, Rens Limpens, Gregory F. Pach, Yaxin Zhai, Matthew C. Beard, Elisa M. Miller, Nathan R. Neale
Summary: This study shows that changing the functional groups on the surface of silicon nanocrystals can slow Auger recombination rates, with thiolate groups elongating the recombination time. These findings highlight the potential positive impact of chemical species with mid-gap surface states under high-rate absorption/emission conditions.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Yu Gan, Yongda Huang, Naihua Miao, Jian Zhou, Zhimei Sun
Summary: A group of 56 novel layered semiconducting IV-V-VI compounds with ultralow lattice thermal conductivity have been predicted through high-throughput ab initio calculations. These compounds exhibit intrinsically low lattice thermal conductivity at room temperature, attributed to avoided-crossing behavior between optical phonons and acoustic modes, leading to significant reduction of phonon group velocities and inducing strong anharmonic phonon-phonon scattering. This work provides a new family of semiconductors with exceptionally low lattice thermal conductivity and emphasizes the design of new low-kappa(l) materials.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Physical
Pengfei Wang, Jing Liu, Wenzhe Shang, Ting Xu, Minhuan Wang, Yantao Shi, Rui Cai, Jiming Bian
Summary: Defect passivation through Lewis acid-base chemistry has attracted significant interest recently due to its ability to improve the power conversion efficiency and stability of perovskite solar cells. This study proposes two typical Lewis base molecules, the M molecule with only carbonyl groups and the 3M molecule with both carbonyl and carboxyl groups, for passivating Pb-based defects and mitigating their negative impacts on PSC performance. The results show that stronger coordination bonds can be formed between the 3M molecule and uncoordinated Pb2+ compared to the M molecule. The synergetic co-passivation effect of carbonyl and carboxyl groups in the 3M modification leads to an impressive maximum PCE of 24.07% and remarkably improved operational stability of the modified devices.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Hyungjin Kim, Shiekh Zia Uddin, Der-Hsien Lien, Matthew Yeh, Nima Sefidmooye Azar, Sivacarendran Balendhran, Taehun Kim, Niharika Gupta, Yoonsoo Rho, Costas P. Grigoropoulos, Kenneth B. Crozier, Ali Javey
Summary: High-performance room-temperature infrared optoelectronic devices with actively variable spectra using black phosphorus demonstrate continuous and reversible tuning of operating wavelengths, as well as multiplexed nondispersive infrared gas sensing capabilities. This platform bridges a technological gap by combining active spectral tunability with high performance, offering a potential way to meet different requirements for emission and detection spectra in optoelectronic applications.
Article
Nanoscience & Nanotechnology
Jarod Meyer, Aaron J. Muhowski, Leland Nordin, Eamonn Hughes, Brian Haidet, Daniel Wasserman, Kunal Mukherjee
Summary: The study focuses on photoluminescence in the mid-wave infrared range from strained thin films of rocksalt PbSe grown on GaAs substrates. Despite high dislocation densities, the films exhibit long minority carrier lifetimes and slow Shockley-Read-Hall recombination, indicating defect tolerance. The results suggest potential for high internal quantum efficiency in these films at room temperature.
Article
Polymer Science
Chai Won Kim, Ji Hye Lee, Seunguk Cho, Hyung Jong Kim, Jinhyo Hwang, Yong Woo Kim, Dae Hyuk Choi, Min Ju Cho, Kwangyeol Lee, Dong Hoon Choi
Summary: The novel hole transport polymer P-CzAc was synthesized for solution-processed green QD-LEDs, exhibiting good solubility and high hole mobility to reduce charge injection barriers and improve device efficiency.
Article
Chemistry, Multidisciplinary
Yuhang Liang, Xiangyuan Cui, Feng Li, Catherine Stampfl, Simon P. Ringer, Jun Huang, Rongkun Zheng
Summary: This study reveals that hydrogen ions, rather than native point defects, act as the dominant nonradiative recombination centers in FAPbI(3) perovskite solar cells. It also suggests that moderate iodine synthesis conditions can suppress the formation of harmful hydrogen ions and improve device performance.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Optics
Bahareh Marzban, Daniela Stange, Denis Rainko, Zoran Ikonic, Dan Buca, Jeremy Witzens
Summary: This study presents a comprehensive modeling of a SiGeSn multi-quantum well laser, revealing low non-radiative lifetime and lower energy separation as key mechanisms limiting laser performance. Additionally, the laser emits in transverse magnetic polarization at higher temperatures.
PHOTONICS RESEARCH
(2021)
Article
Physics, Condensed Matter
Ying Wang, Chen Qiu, Chenhai Shen, Lin Li, Kaike Yang, Zhongming Wei, Hui-Xiong Deng, Congxin Xia
Summary: The band offset trends of IV-VI semiconductors MX and MX2 were investigated, revealing that the valence band offset of MX decreases with increasing atomic number, while that of MX2 remains relatively unchanged. The band edges of the GeX2 system are suitable for photocatalysis, and the band offset modulation in GeSe/SnS and GeSe2/GeS2 heterojunctions makes them suitable for optoelectronic applications.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Yosuke Ishii, Sae Ishikawa, Itta Yamada, Kohei Kondo, Shinya Jindo, Shinji Kawasaki, Yoshiyuki Hattori, Oleksandr Mashkov, Wolfgang Heiss
Summary: Metal nano-particles were prepared by heat-treatment of SWCNTs encapsulating metal complex molecules. The obtained nano-particles were confirmed to be metallic Ni and Cu. The Ni(OH)(2)/SWCNT sample showed promising performance as a high-power battery electrode, while Cu/SWCNT exhibited potential as a CO2 photo-reduction catalyst. The results suggest the significance of using SWCNTs for various applications in energy storage and conversion.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Chemistry, Physical
Wei Meng, Kaicheng Zhang, Andres Osvet, Jiyun Zhang, Wolfgang Gruber, Karen Forberich, Bernd Meyer, Wolfgang Heiss, Tobias Unruh, Ning Li, Christoph J. Brabec
Summary: Identification and investigation of strain at buried interfaces in halide perovskite photovoltaics are crucial for directing research on the performance and stability of perovskite solar cells. In this work, we find that interfacial strain causes a gradual shift in the band gap, which is desired for device engineering. However, the increased defect density leads to charge recombination and ion migration, resulting in decreased performance.
Article
Materials Science, Multidisciplinary
Hany A. Afify, Mykhailo Sytnyk, Viktor Rehm, Anastasiia Barabash, Oleksandr Mashkov, Andres Osvet, Valentine V. Volobuev, Jedrzej Korczak, Andrzej Szczerbakow, Tomasz Story, Klaus Goetz, Tobias Unruh, Christoph Schuesslbauer, Dominik Thiel, Tobias Ullrich, Dirk M. Guldi, Christoph J. Brabec, Wolfgang Heiss
Summary: High-quality epitaxial growth of oriented microcrystallites has been achieved on a semiconductor substrate by drop casting precursor solutions. The microcrystallites exhibit green photoluminescence and lasing with low thresholds. The lasing is stable for over 10^9 excitation pulses, representing an important step towards continuous mode operation or even electrical excitation in future perovskite-based devices.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Sarah Deumel, Yvonne Reg, Judith E. Huerdler, Lukas Hussenether, Oliver Schmidt, Anastasia Barabash, Wolfgang Heiss, Sandro F. Tedde
Summary: Structuring methods of metal-halide perovskites are of great importance for various applications, especially in the field of medical X-ray detection. However, the common techniques are limited to thin layers and new manufacturing strategies, such as laser cutting, are needed. This study shows the potential of using ultrashort pulse laser to structure thick, freestanding methylammonium lead iodide wafers in any configurable geometry. The chosen laser parameters allow shaping of the wafer without significant changes in morphology and X-ray performance.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Hany A. Afify, Viktor Rehm, Anastasiia Barabash, Albert These, Jiyun Zhang, Andres Osvet, Christoph Schuesslbauer, Dominik Thiel, Tobias Ullrich, Martin Dierner, Thomas Przybilla, Johannes Will, Erdmann Spiecker, Dirk M. Guldi, Christoph J. Brabec, Wolfgang Heiss
Summary: This study demonstrates an antisolvent-vapor-assisted crystallization method for epitaxial growth of metal-halide-perovskites. By controlling the shape of micro-crystallites, single-mode operation of lasers with high environmental stability can be achieved, which is competitive with vapor-phase epitaxial microstructures.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jiyun Zhang, Jianchang Wu, Stefan Langner, Baolin Zhao, Zhiqiang Xie, Jens A. Hauch, Hany A. Afify, Anastasia Barabash, Junsheng Luo, Mykhailo Sytnyk, Wei Meng, Kaicheng Zhang, Chao Liu, Andres Osvet, Ning Li, Marcus Halik, Wolfgang Heiss, Yicheng Zhao, Christoph J. Brabec
Summary: This study investigates the thermal stability of a series of quasi-2D perovskites and finds that long-chain cations can suppress thermal aging by hindering lattice rearrangement. On the other hand, short-chain cations promote increased-dimensional phase redistribution, benefiting the regeneration of the perovskite phase. UV-vis absorption spectra, photoluminescence spectra, and X-ray diffraction patterns are used to characterize the impact of steric hindrance on structural reconfiguration and phase redistribution in quasi-2D perovskites. An optimal chain length is identified to maximize film stability by balancing water/oxygen resistance and increased-dimensional phase redistribution.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Editorial Material
Materials Science, Multidisciplinary
Moritz Brehm, Gunther Springholz
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Multidisciplinary Sciences
Geoffroy Kremer, Julian Maklar, Laurent Nicolai, Christopher W. Nicholson, Changming Yue, Caio Silva, Philipp Werner, J. Hugo Dil, Juraj Krempasky, Gunther Springholz, Ralph Ernstorfer, Jan Minar, Laurenz Rettig, Claude Monney
Summary: α-GeTe(111) is a non-centrosymmetric ferroelectric semiconductor material with a strong spin-orbit interaction and giant Rashba coupling. Its ferroelectric polarization can be controlled by an electric field at room temperature, and research shows that femtosecond light pulses can modulate the Rashba coupling and enhance the lattice distortion on a femtosecond timescale.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Olexiy Balitskii, Oleksandr Mashkov, Anastasiia Barabash, Viktor Rehm, Hany A. Afify, Ning Li, Maria S. Hammer, Christoph J. Brabec, Andreas Eigen, Marcus Halik, Olesya Yarema, Maksym Yarema, Vanessa Wood, David Stifter, Wolfgang Heiss
Summary: The study synthesized plasmonic ATO nanocrystals using a solvothermal method and demonstrated ligand exchange as a new strategy for tuning the localized surface plasmon resonance (LSPR) energies. This approach could be important for the development of plasmonic technologies with potential applications such as infrared upconversion, smart glazing, heat absorbers, or thermal barriers.
Article
Physics, Multidisciplinary
R. D. Gonzalez Betancourt, J. Zubac, R. Gonzalez-Hernandez, K. Geishendorf, Z. Soban, G. Springholz, K. Olejnik, L. Smejkal, J. Sinova, T. Jungwirth, S. T. B. Goennenwein, A. Thomas, H. Reichlova, J. Zelezny, D. Kriegner
Summary: A spontaneous anomalous Hall signal was observed in an epitaxial film of MnTe, a semiconductor with collinear antiparallel magnetic ordering and zero net magnetization, even in the absence of an external magnetic field. The anomalous Hall effect originates from the unconventional phase with strong time-reversal symmetry breaking and alternating spin polarization. The anisotropic crystal environment of Mn atoms, caused by nonmagnetic Te atoms, plays a vital role in establishing the unconventional phase and generating the anomalous Hall effect.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Changqing Zhu, Patrick Pilch, Anneke Reinold, Dennis Kudlacik, Gunther Springholz, Alberta Bonanni, Marc Assmann, Mirko Cinchetti, Zhe Wang
Summary: We present a study on the time-resolved optical and terahertz ultrafast spectroscopy of charge-carrier dynamics in the room-temperature antiferromagnetic semiconductor alpha-MnTe. By optically pumping the system with 1.55 eV photons at room temperature, charge carriers are excited in the conduction band and their dynamical response in the nonequilibrium states is investigated using optical and terahertz transmission probes. Three relaxation processes with characteristic relaxation times of approximately 1, 10, and 100 ps are identified, and their exact values depend on the pump fluence. Nonlinear dependence on the pump fluence is observed in both the optical and terahertz probes at high pump fluences.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
J. Bermejo-Ortiz, G. Krizman, R. Jakiela, Z. Khosravizadeh, M. Hajlaoui, G. Bauer, G. Springholz, L. -A. de Vaulchier, Y. Guldner
Summary: On smooth interfaces between a trivial and a topological material, massless Weyl and massive Dirac fermions coexist, with their energy spectra controlled by the smoothness of the topological interface. The optical absorption of the zero-energy chiral Weyl state is also affected by the smoothness of the interface.
Proceedings Paper
Optics
Sarah Deumel, Albert J. J. M. van Breemen, Bart Peeters, Joris Maas, Hylke B. Akkerman, Eric A. Meulenkamp, Gerwin Gelinck, Judith E. Huerdler, Oliver Schmidt, Wolfgang Heiss, Sandro F. Tedde
Summary: This article demonstrates the long-term stability of a pixelated X-ray imaging detector using methylammonium lead triiodide (MAPbI(3)) perovskite. The detector maintains high performance even after being stored under ambient conditions for over a year. However, there is a decrease in X-ray response and sensitivity, indicating a degradation of the perovskite material. The study also investigates the correlated issues of dark current drift and electrical stability.
MEDICAL IMAGING 2022: PHYSICS OF MEDICAL IMAGING
(2022)
Article
Materials Science, Multidisciplinary
S. C. P. van Kooten, G. Springholz, A. B. Henriques
Summary: The study elucidated the spin dynamics involved in the birth and growth of giant spin polarons in a magnetic semiconductor and proposed a new measurement technique. Experimental data and numerical simulations indicated that temperature and fluctuations in the Weiss field play a crucial role in spin coherence generation.
Article
Physics, Multidisciplinary
G. Krizman, B. A. Assaf, M. Orlita, G. Bauer, G. Springholz, R. Ferreira, L. A. de Vaulchier, Y. Guldner
Summary: Topological interface states in multivalley systems are studied using magnetooptical Landau level spectroscopy in topological crystalline insulator heterostructures. The properties of these states are characterized, revealing the factors affecting them in two dimensions.
PHYSICAL REVIEW RESEARCH
(2022)
