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Kang D, Kim Y, Lee M. Laser Dynamic Control of the Thermal Emissivity of a Planar Cavity Structure Based on a Phase-Change Material. ACS APPLIED MATERIALS & INTERFACES 2024; 16:4925-4933. [PMID: 38229510 DOI: 10.1021/acsami.3c16162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Tailoring the thermal emission of a material in the long-wave infrared (IR) range of 8-13 μm is crucial for many IR-adaptive applications, including personal thermal management, IR camouflage, and radiative cooling. Although various materials and surface structures have been proposed for these purposes, space-selective and dynamic control of their emissivity is challenging. In this study, we present a planar surface cavity structure consisting of a Ge2Sb2Te5 (GST) film on top of a thin metal reflector to modulate its emissivity by using an ultraviolet laser beam. A laser-induced phase change in GST allowed for the local control of emissivity. The average emissivity in the long-wave IR range was tunable from 0.15 to 0.77 simply by changing the laser energy deposited on the GST film. This enabled the laser printing of high-contrast emissivity patterns, which were erasable by subsequent thermal annealing. Emissivity-modulated GST cavities could be fabricated on not only rigid substrates but also flexible plastic substrates such as polyimide. The GST surface cavity was highly flexible and remained stable upon repeated bending to a curvature radius of 0.5 cm. This study provides a promising route for realizing scalable and flexible thermal emitters with tunable surface emissivity.
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Affiliation(s)
- Dongkyun Kang
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea
| | - Yeongseon Kim
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea
| | - Myeongkyu Lee
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea
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2
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Shuleiko D, Zabotnov S, Sokolovskaya O, Poliakov M, Volkova L, Kunkel T, Kuzmin E, Danilov P, Kudryashov S, Pepelayev D, Kozyukhin S, Golovan L, Kashkarov P. Hierarchical Surface Structures and Large-Area Nanoscale Gratings in As 2S 3 and As 2Se 3 Films Irradiated with Femtosecond Laser Pulses. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4524. [PMID: 37444839 DOI: 10.3390/ma16134524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023]
Abstract
Chalcogenide vitreous semiconductors (ChVSs) find application in rewritable optical memory storage and optically switchable infrared photonic devices due to the possibility of fast and reversible phase transitions, as well as high refractive index and transmission in the near- and mid-infrared spectral range. Formed on such materials, laser-induced periodic surface structures (LIPSSs), open wide prospects for increasing information storage capacity and create polarization-sensitive optical elements of infrared photonics. In the present work, a possibility to produce LIPSSs under femtosecond laser irradiation (pulse duration 300 fs, wavelength 515 nm, repetition rate up to 2 kHz, pulse energy ranged 0.03 to 0.5 μJ) is demonstrated on a large (up to 5 × 5 mm2) area of arsenic sulfide (As2S3) and arsenic selenide (As2Se3) ChVS films. Scanning electron and atomic force microscopy revealed that LIPSSs with various periods (170-490 nm) and orientations can coexist within the same irradiated region as a hierarchical structure, resulting from the interference of various plasmon polariton modes generated under intense photoexcitation of nonequilibrium carriers within the film. The depth of the structures varied from 30 to 100 nm. The periods and orientations of the formed LIPSSs were numerically simulated using the Sipe-Drude approach. A good agreement of the calculations with the experimental data was achieved.
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Affiliation(s)
- Dmitrii Shuleiko
- Faculty of Physics, Lomonosov Moscow State University, 1/2 Leninskie Gory, 119991 Moscow, Russia
| | - Stanislav Zabotnov
- Faculty of Physics, Lomonosov Moscow State University, 1/2 Leninskie Gory, 119991 Moscow, Russia
| | - Olga Sokolovskaya
- Faculty of Physics, Lomonosov Moscow State University, 1/2 Leninskie Gory, 119991 Moscow, Russia
| | - Maksim Poliakov
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, 16A Nagatinskaya St., 119991 Moscow, Russia
| | - Lidiya Volkova
- Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, 16A Nagatinskaya St., 119991 Moscow, Russia
| | - Tatiana Kunkel
- Moscow Institute of Physics and Technology, 9 Institutskiy Per., 141701 Dolgoprudny, Russia
| | - Evgeny Kuzmin
- Lebedev Physical Institute, The Russian Academy of Science, 53 Leninsky Avenue, 119991 Moscow, Russia
| | - Pavel Danilov
- Lebedev Physical Institute, The Russian Academy of Science, 53 Leninsky Avenue, 119991 Moscow, Russia
| | - Sergey Kudryashov
- Lebedev Physical Institute, The Russian Academy of Science, 53 Leninsky Avenue, 119991 Moscow, Russia
| | - Dmitrii Pepelayev
- Institute of Advanced Materials and Technologies, National Research University of Electronic Technology, 1 Shokina Sq., 124498 Zelenograd, Russia
| | - Sergey Kozyukhin
- Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, 31 Leninsky Avenue, 119991 Moscow, Russia
| | - Leonid Golovan
- Faculty of Physics, Lomonosov Moscow State University, 1/2 Leninskie Gory, 119991 Moscow, Russia
| | - Pavel Kashkarov
- Faculty of Physics, Lomonosov Moscow State University, 1/2 Leninskie Gory, 119991 Moscow, Russia
- National Research Centre "Kurchatov Institute", 1 Akademika Kurchatova Sq., 123182 Moscow, Russia
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Ali A, Piatkowski P, Nawaz T, Ahmad S, Ibrahim T, Khamis M, Alnaser AS. A Two-Step Femtosecond Laser-Based Deposition of Robust Corrosion-Resistant Molybdenum Oxide Coating. MATERIALS (BASEL, SWITZERLAND) 2023; 16:909. [PMID: 36769916 PMCID: PMC9918068 DOI: 10.3390/ma16030909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
A two-step femtosecond-pulsed laser deposition (fs-PLD) process is reported for the rapid development of uniform, poreless, crack-free, and well-adhering amorphous coatings of source materials with a high melting point. The first step comprises a high-rate raw deposition of the source material via fs-PLD, followed by a second step of scanning the raw sample with fs laser pulses of optimized fluence and scan parameters. The technique is applied to develop substoichiometric molybdenum oxide (MoOx, x < 3) coatings on mild steel. The thickness of the layer was ~4.25 μm with roughness around 0.27 μm. Comprehensive surface characterization reveals highly uniform and relatively moderate roughness coatings, implying the potential of these films as robust corrosion-resistant coats. Corrosion measurements in an aqueous NaCl environment revealed that the coated mild steel samples possess an average corrosion inhibition efficiency of around 95% relative to polished mild steel.
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Affiliation(s)
- Asghar Ali
- Department of Physics, American University of Sharjah, Sharjah 26666, United Arab Emirates
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Piotr Piatkowski
- Department of Physics, American University of Sharjah, Sharjah 26666, United Arab Emirates
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Tahir Nawaz
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Shahbaz Ahmad
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Taleb Ibrahim
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Mustafa Khamis
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
- Department of Biology, Chemistry, and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
| | - Ali S. Alnaser
- Department of Physics, American University of Sharjah, Sharjah 26666, United Arab Emirates
- Materials Science and Engineering Program, College of Arts and Sciences, American University of Sharjah, Sharjah 26666, United Arab Emirates
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Wu H, Han W, Zhang X. Ultrafast Dynamics of Different Phase States Ge 2Sb 2Te 5 Film Induced by a Femtosecond Laser Pulse Irradiation. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6760. [PMID: 36234103 PMCID: PMC9572123 DOI: 10.3390/ma15196760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
A femtosecond laser could realize a high transition rate of the phase change material (PCM), and the properties of the amorphous and the crystalline Ge2Sb2Te5 (GST) induced by a femtosecond laser were studied, which was one of the candidates among the PCMs. However, the characteristics of the intermediate phase states in reversible phase transitions were also important and helpful to explore the mechanisms of the phase transitions. In this paper, the ultrafast dynamics of amorphous, crystalline face-centered-cubic (FCC), and hexagonal-close-packed (HCP) states were investigated using a femtosecond laser pulse excitation through a reflective-type pump-probe technique, obtained by annealing at certain temperatures, and verified using X-ray diffraction (XRD) and the Raman spectrum. It was found that as the annealing temperature increased, the electron of the GST films could be excited more easily, while the ablation threshold decreased. Due to annealing, the structure of bonding was changed for different phase states, which resulted in the decrease in the band gap of the films. In addition, it was hard for the intermediate state films to transit to the amorphous structure state via the femtosecond laser, and the crystallization would be enhanced, while the crystalline HCP structures of GST could be directly and easily changed to the amorphous state by a pulse, which resulted from the non-thermal phase change caused by the excited electron.
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Affiliation(s)
- Hao Wu
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China
| | - Weina Han
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China
| | - Xiaobin Zhang
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
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5
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Zhang Y, Liu S, Chen J, Cheng S, Jin W, Zhang Y, Liu Z, Zhang J, Yuan L. All-optically modulated nonvolatile optical switching based on a graded-index multimode fiber. OPTICS EXPRESS 2022; 30:36691-36699. [PMID: 36258592 DOI: 10.1364/oe.468095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/28/2022] [Indexed: 06/16/2023]
Abstract
Photonic switches have attractive application prospects in optical communication data networks that require dynamic reconfiguration. Integrating optical switching devices with optical fiber, the most widely deployed photonic technology platform, can realize signal transmission and processing in practical applications. Here, we demonstrate the multilevel optical switching using the phase-change material Ge2Sb2Te5 (GST) integrated on a graded-index multimode fiber. This switching process works by exploiting the significant difference in extinction coefficient between the crystalline state and the amorphous state of the GST. Using GST to achieve the switch function, no external energy source is needed to maintain the existing state of the switch, and the device is nonvolatile. This multi-level optical switch is an all-fiber integrated device. We apply GST to the end facets of the graded-index multimode fiber by magnetron sputtering, which is a reflective structure. A pulsing scheme is used to control the optical propagation state of the optical modulation signal to realize the switching function. It can store up to 11 non-volatile reliable and repeatable levels encoded by the pump source laser with a wavelength of 1550 nm. At the same time, the switching process between states is on the order of hundreds of nanoseconds. The present experimental results demonstrate the feasibility of 11 multilevel states in the field of optical fibers commonly used in communications. It can be well coupled with the all-fiber terminal device. It also shows that the device is still applicable in the 1525 nm∼1610 nm broadband range, promising for designing future multilevel photonic switches and memory devices.
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Huang H, Zhang P, Tang M, Shen L, Yu Z, Shi H, Tian Y. Biocompatibility of micro/nano structures on the surface of Ti6Al4V and Ti-based bulk metallic glasses induced by femtosecond laser. BIOMATERIALS ADVANCES 2022; 139:212998. [PMID: 35882146 DOI: 10.1016/j.bioadv.2022.212998] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 06/06/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
Femtosecond laser surface modification has been proved to be a versatile technology to create various functional materials by modifying solid surface properties. An interesting experimental phenomenon is found by exposing a Ti6Al4V alloy and Ti-based metallic glass to femtosecond laser irradiation. The research results show that the femtosecond laser induces different micro-nano structures on the surfaces of Ti6Al4V alloy and Ti-based metallic glass. Spherical structure and LIPSS (Laser-induced periodic surface structures) can be formed on the surface of Ti6Al4V alloy after femtosecond laser irradiation. On the surface of Ti-based metallic glass, LIPSS, SWPSS (Super-wavelength periodic surface structure) and neatly arranged microholes structures can be found. Under the same laser parameters, the micro-nano structures showed different evolution trends on the Ti6Al4V alloy and Ti-based metallic glass surfaces. The difference in surface structure between Ti6Al4V alloy and Ti-based metallic glass is since amorphous materials have no crystal lattice and a fixed melting temperature. In addition, there are differences in the biocompatibility of different surface structures. The size and distance of the micro-pits on the surface of different structures determine the ability of cells to adhesion, proliferate and differentiate. This conclusion has important significance for the application of Ti6Al4V alloy and Ti-based metallic glass in the field of biomedicine.
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Affiliation(s)
- Hanxuan Huang
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China
| | - Peilei Zhang
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China; Fraunhofer Institute for Laser Technology ILT, Aachen 52074, Germany.
| | - Man Tang
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China
| | - Lei Shen
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China
| | - Zhishui Yu
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China.
| | - Haichuan Shi
- School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; Shanghai Collaborative Innovation Center of Laser of Manufacturing Technology, Shanghai 201620, China
| | - Yingtao Tian
- Department of Engineering, Lancaster University, Lancaster LA1 4YW, United Kingdom
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7
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Du J, Zhou J, Zhang L, Yang N, Ding X, Zhang J. Investigation of the Crystallization Characteristics of Intermediate States in Ge 2Sb 2Te 5 Thin Films Induced by Nanosecond Multi-Pulsed Laser Irradiation. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:536. [PMID: 35159881 PMCID: PMC8839464 DOI: 10.3390/nano12030536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/02/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023]
Abstract
Laser pulses can be utilized to induce intermediate states of phase change materials between amorphous and crystalline phases, making phase change materials attractive and applicable for multi-level storage applications. In this paper, intermediate states of Ge2Sb2Te5 thin films induced via employing a nanosecond multi-pulse laser with different energy and pulse duration were performed by Raman spectroscopy, reflection measurement and thermal simulations. Upon laser-crystallized Ge2Sb2Te5 films, optical functions change drastically, leading to distinguishable reflectivity contrasts of intermediate states between amorphous and crystalline phases due to different crystallinity. The changes in optical intensity for laser-crystallized Ge2Sb2Te5 are also accompanied by micro-structure evolution, since high-energy and longer pulses result in higher-level intermediate states (corresponding to high reflection intensity) and largely contribute to the formation of stronger Raman peaks. By employing thermal analysis, we further demonstrated that the variations of both laser fluence and pulse duration play decisive roles in the degree of crystallinity of Ge2Sb2Te5 films. Laser fluence is mainly responsible for the variations in crystallization temperature, while the varying pulse duration has a great impact on the crystallization time. The present study offers a deeper understanding of the crystallization characteristic of phase change material Ge2Sb2Te5.
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Affiliation(s)
- Jia Du
- Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093, China; (J.Z.); (L.Z.); (N.Y.); (X.D.); (J.Z.)
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8
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Zhou W, Zhang Z, Zhang Q, Qi D, Xu T, Dai S, Shen X. Transient Study of Femtosecond Laser-Induced Ge 2Sb 2Te 5 Phase Change Film Morphology. MICROMACHINES 2021; 12:mi12060616. [PMID: 34071820 PMCID: PMC8229194 DOI: 10.3390/mi12060616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/05/2021] [Accepted: 04/11/2021] [Indexed: 11/16/2022]
Abstract
Femtosecond laser-induced crystallization and ablation of Ge2Sb2Te5 (GST) phase change film is investigated by reflectivity pump-probing technology. Below the ablation threshold, the face-centered cubic structure (FCC) state in the central area can be formed, and cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter. The time of surface temperature dropping to the crystallization point needs about 30 ps for 5.86 mJ/cm2 and 82 ps for 7.04 mJ/cm2, respectively. At higher laser fluence, crystallization GST island structures appear in the central ablation region due to the extremely short heating time (100 ps). Furthermore, crystallization rate is faster than the ablation rate of the GST film, which is caused by different reflectivity.
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Affiliation(s)
- Wenju Zhou
- Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China; (W.Z.); (Q.Z.); (S.D.); (X.S.)
- Center for Advanced Laser Manufacturing (CALM), Shandong University of Technology, Zibo 255000, China
| | - Zifeng Zhang
- College of Mechanical and Electronic Engineering, Chaohu University, Hefei 230000, China;
| | - Qingwei Zhang
- Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China; (W.Z.); (Q.Z.); (S.D.); (X.S.)
| | - Dongfeng Qi
- Center for Advanced Laser Manufacturing (CALM), Shandong University of Technology, Zibo 255000, China
- Correspondence: (D.Q.); (T.X.)
| | - Tianxiang Xu
- Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China; (W.Z.); (Q.Z.); (S.D.); (X.S.)
- Correspondence: (D.Q.); (T.X.)
| | - Shixun Dai
- Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China; (W.Z.); (Q.Z.); (S.D.); (X.S.)
| | - Xiang Shen
- Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China; (W.Z.); (Q.Z.); (S.D.); (X.S.)
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9
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Julian MN, Williams C, Borg S, Bartram S, Kim HJ. Reversible optical tuning of GeSbTe phase-change metasurface spectral filters for mid-wave infrared imaging. OPTICA 2020; 7:746-754. [PMID: 34277892 PMCID: PMC8262593 DOI: 10.1364/optica.392878] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/08/2020] [Accepted: 06/07/2020] [Indexed: 05/29/2023]
Abstract
Tunable narrowband spectral filtering across arbitrary optical wavebands is highly desirable in a plethora of applications, from chemical sensing and hyperspectral imaging to infrared astronomy. Yet, the ability to reconfigure the optical properties, with full reversibility, of a solid-state large-area narrowband filter remains elusive. Existing solutions require either moving parts, have slow response times, or provide limited spectral coverage. Here, we demonstrate a 1-inch diameter continuously tunable, fully reversible, all-solid-state, narrowband phase-change metasurface filter based on a GeSbTe-225 (GST)-embedded plasmonic nanohole array. The passband of the presented device is ∼ 74 n m with ∼ 70 % transmittance and operates across the 3-5 µm thermal imaging waveband. Continuous, reconfigurable tuning is achieved by exploiting intermediate GST phases via optical switching with a single nanosecond laser pulse, and material stability is verified through multiple switching cycles. We further demonstrate multispectral thermal imaging in the mid-wave infrared using our active phase-change metasurfaces. Our results pave the way for highly functional, reduced power, compact hyperspectral imaging systems and customizable optical filters for real-world system integration.
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Affiliation(s)
- Matthew N. Julian
- Charles L. Brown Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904,
USA
- National Institute of Aerospace, Hampton, Virginia 23666,
USA
| | - Calum Williams
- Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE,
UK
| | - Stephen Borg
- NASA Langley Research Center, Hampton, Virginia 23666,
USA
| | - Scott Bartram
- NASA Langley Research Center, Hampton, Virginia 23666,
USA
| | - Hyun Jung Kim
- National Institute of Aerospace, Hampton, Virginia 23666,
USA
- NASA Langley Research Center, Hampton, Virginia 23666,
USA
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Lotnyk A, Behrens M, Rauschenbach B. Phase change thin films for non-volatile memory applications. NANOSCALE ADVANCES 2019; 1:3836-3857. [PMID: 36132100 PMCID: PMC9419560 DOI: 10.1039/c9na00366e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
The rapid development of Internet of Things devices requires real time processing of a huge amount of digital data, creating a new demand for computing technology. Phase change memory technology based on chalcogenide phase change materials meets many requirements of the emerging memory applications since it is fast, scalable and non-volatile. In addition, phase change memory offers multilevel data storage and can be applied both in neuro-inspired and all-photonic in-memory computing. Furthermore, phase change alloys represent an outstanding class of functional materials having a tremendous variety of industrially relevant characteristics and exceptional material properties. Many efforts have been devoted to understanding these properties with the particular aim to design universal memory. This paper reviews materials science aspects of chalcogenide-based phase change thin films relevant for non-volatile memory applications. Particular emphasis is put on local structure, control of disorder and its impact on material properties, order-disorder transitions and interfacial transformations.
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Affiliation(s)
- A Lotnyk
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
| | - M Behrens
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
| | - B Rauschenbach
- Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig Germany
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11
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Madhavan VE, Carignano M, Kachmar A, Sangunni KS. Crystallization properties of arsenic doped GST alloys. Sci Rep 2019; 9:12985. [PMID: 31506508 PMCID: PMC6737191 DOI: 10.1038/s41598-019-49168-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 08/15/2019] [Indexed: 11/17/2022] Open
Abstract
We present the enhanced properties observed in the phase change memory alloy Ge2Sb2Te5 (GST) when doped with arsenic. Although arsenic is known as a toxic element, our observations show that significant improvement can be obtained in GST systems on thermal stability, transition temperature between amorphous and crystalline phases and switching behaviors when doping with arsenic. Though both the GST and arsenic doped GST are amorphous in the as-deposited state, only GST alloy turns to crystalline NaCl-type structure after annealing at 150 °C for 1 h. Results from the resistance versus temperature study show a systematic increase in the transition temperature and resistivity in the amorphous and crystalline states when the arsenic percentage in the GST alloy increases. The crystallization temperature (Tc) of (GST)0.85As0.15 is higher than the Tc observed in GST. Optical band gap (Eopt) values of the as-deposited films show a clear increasing trend; 0.6 eV for GST to 0.76 eV for (GST)0.85As0.15. The decreases in Eopt for the samples annealed at higher temperatures shows significant optical contrast between the as-deposited and annealed samples. Though all (GST)1-xAsx alloys show memory switching behaviors, threshold switching voltages (VT) of the studied alloys show an increasing trend with arsenic doping. For (GST)0.85As0.15, VT is about 5.2 V, which is higher than GST (4.0 V). Higher transition temperature and higher threshold switching values show arsenic doping in GST can enhance the memory device properties by improving the thermal stability and data readability. Understanding the doping effect on the GST is important to understand its crystallization properties. Structure properties of amorphous GST, Ge2Sb2-0.3As0.3Te5 and (GST)0.85As0.15 models were studied using first principles molecular dynamics simulations, compared their partial radial distribution functions, and q parameter order. Arsenic doping into GST features interesting structural and electronic effects revealed by the radial distribution functions, q order parameter and band gap value, in line with the experimental findings.
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Affiliation(s)
- Vinod E Madhavan
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, P. O. Box 34110, Doha, Qatar.
| | - Marcelo Carignano
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, P. O. Box 34110, Doha, Qatar
| | - Ali Kachmar
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, P. O. Box 34110, Doha, Qatar.
| | - K S Sangunni
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India
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12
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Behrens M, Lotnyk A, Gerlach JW, Hilmi I, Abel T, Lorenz P, Rauschenbach B. Ultrafast interfacial transformation from 2D- to 3D-bonded structures in layered Ge-Sb-Te thin films and heterostructures. NANOSCALE 2018; 10:22946-22953. [PMID: 30500030 DOI: 10.1039/c8nr06567e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Two-dimensional van-der-Waals-bonded chalcogenide heterostructures have recently received a lot of attention due to promising applications in the fields of photonics, plasmonics and data storage. Of particular interest is the interfacial switching process inherent in these structures, which is assumed to occur locally at the van-der-Waals interfaces and thus represents an intracrystalline transition. However, detailed experimental studies on the underlying mechanism are still lacking. In this work, epitaxially grown thin films consisting of van-der-Waals-bonded Ge-Sb-Te and GeTe/Sb2Te3 based heterostructures are employed as a model system to investigate structural changes induced by a single ns-laser pulse. A combined approach using X-ray diffraction and advanced transmission electron microscopy is applied to study phase transitions within the Ge-Sb-Te-based thin films in detail. The results reveal ultrafast transitions from 2D-bonded layered structures to 3D-bonded structures via a transient molten phase. Moreover, the interface between the 2D- and 3D-bonded structures is well defined by a single van-der-Waals gap, suggesting that the transition can be controlled very precisely in its spatial extent by an appropriate choice of the laser fluence. Overall, the results of this work offer a new perspective on the switching mechanism in Ge-Sb-Te-based materials and demonstrate the potential of van-der-Waals-bonded Ge-Sb-Te compounds to be applied for novel phase-change memory concepts.
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Affiliation(s)
- Mario Behrens
- Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, D-04318 Leipzig, Germany.
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13
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Wang G, Li C, Shi D, Zhang Y, Shen X. Laser-induced metastable phase in crystalline phase-change films by confocal Raman spectrometer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 205:551-556. [PMID: 30075435 DOI: 10.1016/j.saa.2018.07.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Understanding crystallization process in phase-change materials is very important for data storage application. Especially, accurately controlling the metastable phase transition as well as characterizing its structure evolution is still under investigation. In this study, phase transformations have occurs from amorphous to crystalline phases when the phase-change films were irradiated continuously by the 785 nm laser irradiation. By adjusting the laser power, the different metastable phases in conventional Ge2Sb2Te5, Sb2Te3, ZnSb, ZnSb-Al2O3 and ZnSb-ZnO were obtained and distinguished by their different Raman vibration modes. The effect of laser power on the phase-change threshold of these films was studied systematically. Large structural differences induced by laser irradiation were revealed based on the changes in Raman profiles. Our study may offer a new insight into an accurate control of distinct metastable state to realize optical multilevel memory.
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Affiliation(s)
- Guoxiang Wang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China.
| | - Chao Li
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China
| | - Daotian Shi
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China
| | - Yawen Zhang
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China
| | - Xiang Shen
- Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China.
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Sahu S, Sharma R, Adarsh KV, Manivannan A. Ultrafast and low-power crystallization in Ge 1Sb 2Te 4 and Ge 1Sb 4Te 7 thin films using femtosecond laser pulses. APPLIED OPTICS 2018; 57:178-184. [PMID: 29328161 DOI: 10.1364/ao.57.000178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/03/2017] [Indexed: 06/07/2023]
Abstract
Rapid and reversible switching between amorphous and crystalline phases of phase-change material promises to revolutionize the field of information processing with a wide range of applications including electronic, optoelectronics, and photonic memory devices. However, achieving faster crystallization is a key challenge. Here, we demonstrate femtosecond-driven transient inspection of ultrafast crystallization of as-deposited amorphous Ge1Sb2Te4 and Ge1Sb4Te7 thin films induced by a series of 120 fs laser pulses. The snapshots of phase transitions are correlated with the time-resolved measurements of change in the absorption of the samples. The crystallization is attributed to the reiterative excitation of an intermediate state with subcritical nuclei at a strikingly low fluence of 3.19 mJ/cm2 for Ge1Sb2Te4 and 1.59 mJ/cm2 for Ge1Sb4Te7. Furthermore, 100% volumetric crystallization of Ge1Sb4Te7 was achieved with the fluence of 4.78 mJ/cm2, and also reamorphization is seen for a continuous stimulation at the same repetition rate and fluence. A systematic confirmation of structural transformations of all samples is validated by Raman spectroscopic measurements on the spots produced by the various excitation fluences.
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Behrens M, Lotnyk A, Roß U, Griebel J, Schumacher P, Gerlach JW, Rauschenbach B. Impact of disorder on optical reflectivity contrast of epitaxial Ge2Sb2Te5 thin films. CrystEngComm 2018. [DOI: 10.1039/c8ce00534f] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Classification of the optical reflectivity contrasts of single-phase, epitaxial Ge2Sb2Te5 thin films with respect to the vacancy arrangements.
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Affiliation(s)
- Mario Behrens
- Leibniz Institute of Surface Engineering (IOM)
- 04318 Leipzig
- Germany
| | - Andriy Lotnyk
- Leibniz Institute of Surface Engineering (IOM)
- 04318 Leipzig
- Germany
| | - Ulrich Roß
- Leibniz Institute of Surface Engineering (IOM)
- 04318 Leipzig
- Germany
| | - Jan Griebel
- Leibniz Institute of Surface Engineering (IOM)
- 04318 Leipzig
- Germany
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Sahu S, Sharma R, Adarsh KV, Manivannan A. Femtosecond laser-induced ultrafast transient snapshots and crystallization dynamics in phase change material. OPTICS LETTERS 2017; 42:2503-2506. [PMID: 28957269 DOI: 10.1364/ol.42.002503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
We report here femtosecond laser-driven transient snapshots of ultrafast crystallization of Ge2Sb2Te5 films from its as-deposited amorphous phase, and the local structural change is validated by micro-Raman spectroscopy and x-ray diffraction. The decay time constant of ∼5 ps in transient spectra with a precise temporal resolution using 400 nm (pump) reveals about 68 volumetric percentage crystallization at a remarkably low fluence of 4.78 mJ·cm-2. This is attributed to reiterated excitation after a complete carrier relaxation and formation of a long-lasting transient phase at sub-threshold fluences. Furthermore, Raman spectra of irradiated spots confirm defective-octahedral modes at 110 and 160 cm-1 validating crystallization.
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