Sung‐Han Jeon, Dae-Hwan Ahn, Kyul Ko, Won Jun Choi, Jinlai Song, Woo-Young Choi, Jae‐Hoon Han
A high‐responsivity photo‐field‐effect transistor (photo‐FET) with a metal‐oxide‐semiconductor (MOS) structure is a promising technology for low‐intensity light detection with its high gain and low operation voltage. To enhance their responsivity, the equivalent oxide thickness (EOT) scaling is one of the effective solutions, which is a common technology to improve the electrical properties of MOSFETs using higher‐k insulators. Herein, the EOT scaling effect on the optoelectrical characteristics of photo‐FETs using Al2O3 and Al2O3/HfO2 gate stacks is investigated. Thanks to the EOT scaling effect introducing Al2O3/HfO2, only the transconductance of the photo‐FET is enhanced without any significant change in the photovoltaic effect and cavity effect. As a result, its responsivity is improved by up to 1.7 times. The results give a basic strategy of the EOT scaling effect for photo‐FETs; thus, the EOT scaling with a higher‐k insulator is a powerful solution for the high‐performance InGaAs photo‐FET requiring high responsivity in the short‐wavelength infrared range.
采用金属氧化物半导体（MOS）结构的高响应率光电场效应晶体管（photo-FET）具有增益高、工作电压低的特点，是一种很有前途的低强度光探测技术。为了提高其响应率，等效氧化物厚度（EOT）缩放是有效的解决方案之一，这也是利用更高 k 绝缘体改善 MOSFET 电性能的常用技术。本文研究了等效氧化物厚度缩放对使用 Al2O3 和 Al2O3/HfO2 栅极叠层的光 FET 光电特性的影响。由于引入了 Al2O3/HfO2 的 EOT 缩放效应，只提高了光 FET 的跨导，而光电效应和空穴效应却没有显著变化。因此，其响应率最高提高了 1.7 倍。这些结果给出了光场效应晶体管 EOT 缩放效应的基本策略；因此，对于要求在短波长红外范围内具有高响应率的高性能 InGaAs 光场效应晶体管来说，使用更高 k 值绝缘体进行 EOT 缩放是一种强有力的解决方案。
{"title":"Responsivity Enhancement of Wafer‐Bonded In0.53Ga0.47As Photo‐Field‐Effect Transistor on Si Substrate via Equivalent Oxide Thickness Scaling","authors":"Sung‐Han Jeon, Dae-Hwan Ahn, Kyul Ko, Won Jun Choi, Jinlai Song, Woo-Young Choi, Jae‐Hoon Han","doi":"10.1002/pssa.202300664","DOIUrl":"https://doi.org/10.1002/pssa.202300664","url":null,"abstract":"A high‐responsivity photo‐field‐effect transistor (photo‐FET) with a metal‐oxide‐semiconductor (MOS) structure is a promising technology for low‐intensity light detection with its high gain and low operation voltage. To enhance their responsivity, the equivalent oxide thickness (EOT) scaling is one of the effective solutions, which is a common technology to improve the electrical properties of MOSFETs using higher‐k insulators. Herein, the EOT scaling effect on the optoelectrical characteristics of photo‐FETs using Al2O3 and Al2O3/HfO2 gate stacks is investigated. Thanks to the EOT scaling effect introducing Al2O3/HfO2, only the transconductance of the photo‐FET is enhanced without any significant change in the photovoltaic effect and cavity effect. As a result, its responsivity is improved by up to 1.7 times. The results give a basic strategy of the EOT scaling effect for photo‐FETs; thus, the EOT scaling with a higher‐k insulator is a powerful solution for the high‐performance InGaAs photo‐FET requiring high responsivity in the short‐wavelength infrared range.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139870890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sung‐Han Jeon, Dae-Hwan Ahn, Kyul Ko, Won Jun Choi, Jinlai Song, Woo-Young Choi, Jae‐Hoon Han
A high‐responsivity photo‐field‐effect transistor (photo‐FET) with a metal‐oxide‐semiconductor (MOS) structure is a promising technology for low‐intensity light detection with its high gain and low operation voltage. To enhance their responsivity, the equivalent oxide thickness (EOT) scaling is one of the effective solutions, which is a common technology to improve the electrical properties of MOSFETs using higher‐k insulators. Herein, the EOT scaling effect on the optoelectrical characteristics of photo‐FETs using Al2O3 and Al2O3/HfO2 gate stacks is investigated. Thanks to the EOT scaling effect introducing Al2O3/HfO2, only the transconductance of the photo‐FET is enhanced without any significant change in the photovoltaic effect and cavity effect. As a result, its responsivity is improved by up to 1.7 times. The results give a basic strategy of the EOT scaling effect for photo‐FETs; thus, the EOT scaling with a higher‐k insulator is a powerful solution for the high‐performance InGaAs photo‐FET requiring high responsivity in the short‐wavelength infrared range.
采用金属氧化物半导体（MOS）结构的高响应率光电场效应晶体管（photo-FET）具有增益高、工作电压低的特点，是一种很有前途的低强度光探测技术。为了提高其响应率，等效氧化物厚度（EOT）缩放是有效的解决方案之一，这也是利用更高 k 绝缘体改善 MOSFET 电性能的常用技术。本文研究了等效氧化物厚度缩放对使用 Al2O3 和 Al2O3/HfO2 栅极叠层的光 FET 光电特性的影响。由于引入了 Al2O3/HfO2 的 EOT 缩放效应，只提高了光 FET 的跨导，而光电效应和空穴效应却没有显著变化。因此，其响应率最高提高了 1.7 倍。这些结果给出了光场效应晶体管 EOT 缩放效应的基本策略；因此，对于要求在短波长红外范围内具有高响应率的高性能 InGaAs 光场效应晶体管来说，使用更高 k 值绝缘体进行 EOT 缩放是一种强有力的解决方案。
{"title":"Responsivity Enhancement of Wafer‐Bonded In0.53Ga0.47As Photo‐Field‐Effect Transistor on Si Substrate via Equivalent Oxide Thickness Scaling","authors":"Sung‐Han Jeon, Dae-Hwan Ahn, Kyul Ko, Won Jun Choi, Jinlai Song, Woo-Young Choi, Jae‐Hoon Han","doi":"10.1002/pssa.202300664","DOIUrl":"https://doi.org/10.1002/pssa.202300664","url":null,"abstract":"A high‐responsivity photo‐field‐effect transistor (photo‐FET) with a metal‐oxide‐semiconductor (MOS) structure is a promising technology for low‐intensity light detection with its high gain and low operation voltage. To enhance their responsivity, the equivalent oxide thickness (EOT) scaling is one of the effective solutions, which is a common technology to improve the electrical properties of MOSFETs using higher‐k insulators. Herein, the EOT scaling effect on the optoelectrical characteristics of photo‐FETs using Al2O3 and Al2O3/HfO2 gate stacks is investigated. Thanks to the EOT scaling effect introducing Al2O3/HfO2, only the transconductance of the photo‐FET is enhanced without any significant change in the photovoltaic effect and cavity effect. As a result, its responsivity is improved by up to 1.7 times. The results give a basic strategy of the EOT scaling effect for photo‐FETs; thus, the EOT scaling with a higher‐k insulator is a powerful solution for the high‐performance InGaAs photo‐FET requiring high responsivity in the short‐wavelength infrared range.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"23 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139811174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Zainal, S. Hagedorn, C. Netzel, T. Kolbe, Markus Weyers
This study explores the impact of Si doping on the material properties of high‐temperature annealed (HTA) Al0.71Ga0.29N layers, which are grown on AlN/sapphire templates. The AlGaN layers are doped with Si by applying different IV/III ratios during epitaxial growth and compared to undoped Al0.71Ga0.29N. Before HTA, the threading dislocation density (TDD) for all samples is about 6.0 × 109 cm−2. After HTA, the Si‐doped AlGaN grown with the highest IV/III ratio of 3.6 × 104 shows the lowest TDD of 1.2 × 109 cm−2. Secondary ion mass spectrometry depth profiles reveal an accelerated Ga diffusion from the doped AlGaN into the AlN buffer layer compared to undoped AlGaN. This suggests that the Ga diffusion process is mediated by Si diffusion. Consequently, the Ga diffusion leads to a decrease in the Ga mole fraction of annealed Si‐doped AlGaN. Furthermore, strain relaxation is higher for the Si‐doped AlGaN than for the undoped AlGaN, before and after HTA. The results from this study suggest that Si doping can be a new promising approach in enhancing the quality of HTA‐AlGaN as a useful template for the growth of UV LED heterostructures.
{"title":"High‐Temperature Annealing of Si‐Doped AlGaN","authors":"N. Zainal, S. Hagedorn, C. Netzel, T. Kolbe, Markus Weyers","doi":"10.1002/pssa.202300897","DOIUrl":"https://doi.org/10.1002/pssa.202300897","url":null,"abstract":"This study explores the impact of Si doping on the material properties of high‐temperature annealed (HTA) Al0.71Ga0.29N layers, which are grown on AlN/sapphire templates. The AlGaN layers are doped with Si by applying different IV/III ratios during epitaxial growth and compared to undoped Al0.71Ga0.29N. Before HTA, the threading dislocation density (TDD) for all samples is about 6.0 × 109 cm−2. After HTA, the Si‐doped AlGaN grown with the highest IV/III ratio of 3.6 × 104 shows the lowest TDD of 1.2 × 109 cm−2. Secondary ion mass spectrometry depth profiles reveal an accelerated Ga diffusion from the doped AlGaN into the AlN buffer layer compared to undoped AlGaN. This suggests that the Ga diffusion process is mediated by Si diffusion. Consequently, the Ga diffusion leads to a decrease in the Ga mole fraction of annealed Si‐doped AlGaN. Furthermore, strain relaxation is higher for the Si‐doped AlGaN than for the undoped AlGaN, before and after HTA. The results from this study suggest that Si doping can be a new promising approach in enhancing the quality of HTA‐AlGaN as a useful template for the growth of UV LED heterostructures.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"458 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140476939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Threshold voltage is an essential component for a transistor to operate properly. In this work, an alternate technique for obtaining the threshold voltage, which is referred to as the conductance–voltage method, is suggested. In this technique, the threshold voltage is estimated by measuring the change in drain current with an applied gate voltage when the device transits from the weak accumulation to the strong accumulation mode of operation. The 2D simulations are then used to apply this strategy to pentacene‐based and amorphous indium‐gallium‐zinc‐oxide‐based thin‐film transistors (TFTs) in their linear region of operation. These seem promising, and the technique offers a useful tool for enhancing the functionality of complementary organic/oxide TFTs in the future.
{"title":"Threshold Voltage Extraction Using Conductance–Voltage Method for Nano‐Organic/Oxide Thin‐Film Transistors: Comparative Study of P‐ and N‐Type Devices","authors":"Illa Pream Krishna, R. Agarwal","doi":"10.1002/pssa.202300746","DOIUrl":"https://doi.org/10.1002/pssa.202300746","url":null,"abstract":"Threshold voltage is an essential component for a transistor to operate properly. In this work, an alternate technique for obtaining the threshold voltage, which is referred to as the conductance–voltage method, is suggested. In this technique, the threshold voltage is estimated by measuring the change in drain current with an applied gate voltage when the device transits from the weak accumulation to the strong accumulation mode of operation. The 2D simulations are then used to apply this strategy to pentacene‐based and amorphous indium‐gallium‐zinc‐oxide‐based thin‐film transistors (TFTs) in their linear region of operation. These seem promising, and the technique offers a useful tool for enhancing the functionality of complementary organic/oxide TFTs in the future.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"9 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139607570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shyam Mohan, Joocheol Jeong, Minho Kim, Yunseok Heo, Jooyong Park, Joonhyuk Lee, Jinwan Kim, Jeonghun Heo, Okhyun Nam
This study focuses on investigating the size‐dependent characteristics (chip diameter: 100–10 μm) of InGaN‐based blue and green micro‐light‐emitting diodes (μLEDs) with respect to their electrical and optical properties. The LED's epistructure is grown using the metal–organic chemical vapor deposition technique, preceded by simulation and optimization using SiLENSe LED simulator. The cross‐sectional transmission electron microscopy study confirms the epistructure. The Photoluminescence mapping of the epistructure reveals that the blue emission is at 461 nm (full width at half maximum [FWHM] ≈ 15.5 nm) and the green emission is at 510 nm (FWHM ≈ 17.5 nm). The study analyzes the size‐dependent external quantum efficiency (EQE), optical power, and peak wavelength shift between blue and green μLEDs. The electroluminescence (EL) study reveals that the redshift of the EL peak wavelength of μLEDs is attributed to the release of strain at reduced chip sizes. The size‐dependent EQE study shows a reduction of EQE with shrunken chip size, attributed to the increase of nonradiative Shockley–Read–Hall recombination. Finally, the study estimates the characteristics temperature of the μLEDs using temperature‐dependent EL measurement, revealing that blue μLEDs exhibit a significantly large value of characteristic temperature ≈1926 K.
{"title":"Size‐Dependent Characteristics of InGaN‐Based Blue and Green Micro‐Light‐Emitting Diodes","authors":"Shyam Mohan, Joocheol Jeong, Minho Kim, Yunseok Heo, Jooyong Park, Joonhyuk Lee, Jinwan Kim, Jeonghun Heo, Okhyun Nam","doi":"10.1002/pssa.202300642","DOIUrl":"https://doi.org/10.1002/pssa.202300642","url":null,"abstract":"This study focuses on investigating the size‐dependent characteristics (chip diameter: 100–10 μm) of InGaN‐based blue and green micro‐light‐emitting diodes (μLEDs) with respect to their electrical and optical properties. The LED's epistructure is grown using the metal–organic chemical vapor deposition technique, preceded by simulation and optimization using SiLENSe LED simulator. The cross‐sectional transmission electron microscopy study confirms the epistructure. The Photoluminescence mapping of the epistructure reveals that the blue emission is at 461 nm (full width at half maximum [FWHM] ≈ 15.5 nm) and the green emission is at 510 nm (FWHM ≈ 17.5 nm). The study analyzes the size‐dependent external quantum efficiency (EQE), optical power, and peak wavelength shift between blue and green μLEDs. The electroluminescence (EL) study reveals that the redshift of the EL peak wavelength of μLEDs is attributed to the release of strain at reduced chip sizes. The size‐dependent EQE study shows a reduction of EQE with shrunken chip size, attributed to the increase of nonradiative Shockley–Read–Hall recombination. Finally, the study estimates the characteristics temperature of the μLEDs using temperature‐dependent EL measurement, revealing that blue μLEDs exhibit a significantly large value of characteristic temperature ≈1926 K.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"116 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139614382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vitalii A. Kuznetsov, M. Gudkov, Vladimir A. Ermakov, K. Shiyanova, Lidiya V. Shestopalova, Andrey A. Fedorov, Evgeny Yu. Gerasimov, Evgenii A. Suprun
Polymer composites of a segregated network structure are dielectric polymer granules coated with electrically conductive nanoparticles at a low content, the quantity of the junctions between the granules determines the composites' mechanical properties, and the percolation network formed by the nanoparticles determines the electrical conductivity. Here, the morphology and electron‐transport properties in reduced graphene oxide (rGO)‐filled composites with a segregated structure based on polyvinyl chloride (PVC), poly(vinylidene fluoride‐co‐tetrafluoroethylene) (P(VDF‐TFE)), and ultrahigh‐molecular‐weight polyethylene (UHMWPE) are studied. Optical and electron microscopies study of the microtome‐formed cross sections have shown the morphology to be dependent on the polymer—the thinnest rGO layers are in UHMWPE‐based composites, the thicker rGO layers are in PVC‐ and P(VDF‐TFE)‐based ones. The electrical conduction of the composites and the rGO‐paper occurs through the same hopping conduction mechanisms within the wide temperature range, which allows to use the composites in applications where pure rGO is considered. Owing to thicker rGO layers open to the environment, PVC‐ and P(VDF‐TFE)‐based composites are more attractive, rather than the UHMWPE ones, in applications where layered materials are needed, for example, in lithium‐ion batteries or supercapacitors. The UHMWPE‐based composites look more promising as electrically conductive materials when mechanical strength is important.
{"title":"Detailed Morphology and Electron Transport in Reduced Graphene Oxide Filled Polymer Composites with a Segregated Structure","authors":"Vitalii A. Kuznetsov, M. Gudkov, Vladimir A. Ermakov, K. Shiyanova, Lidiya V. Shestopalova, Andrey A. Fedorov, Evgeny Yu. Gerasimov, Evgenii A. Suprun","doi":"10.1002/pssa.202300855","DOIUrl":"https://doi.org/10.1002/pssa.202300855","url":null,"abstract":"Polymer composites of a segregated network structure are dielectric polymer granules coated with electrically conductive nanoparticles at a low content, the quantity of the junctions between the granules determines the composites' mechanical properties, and the percolation network formed by the nanoparticles determines the electrical conductivity. Here, the morphology and electron‐transport properties in reduced graphene oxide (rGO)‐filled composites with a segregated structure based on polyvinyl chloride (PVC), poly(vinylidene fluoride‐co‐tetrafluoroethylene) (P(VDF‐TFE)), and ultrahigh‐molecular‐weight polyethylene (UHMWPE) are studied. Optical and electron microscopies study of the microtome‐formed cross sections have shown the morphology to be dependent on the polymer—the thinnest rGO layers are in UHMWPE‐based composites, the thicker rGO layers are in PVC‐ and P(VDF‐TFE)‐based ones. The electrical conduction of the composites and the rGO‐paper occurs through the same hopping conduction mechanisms within the wide temperature range, which allows to use the composites in applications where pure rGO is considered. Owing to thicker rGO layers open to the environment, PVC‐ and P(VDF‐TFE)‐based composites are more attractive, rather than the UHMWPE ones, in applications where layered materials are needed, for example, in lithium‐ion batteries or supercapacitors. The UHMWPE‐based composites look more promising as electrically conductive materials when mechanical strength is important.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"123 46","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139614864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuki Adachi, Issei Sada, M. Morifuji, H. Kajii, Akihiro Maruta, Masahiko Kondow
We aim to achieve wavelength division multiplexing with a circular defect in two‐dimensional photonic crystal (CirD) laser that has an orthogonal lattice waveguide (OLW). In a simulation, we calculate the output extraction efficiency to discover a structure in which stronger optical output can be extracted for the CirD laser with OLW. Consequently, adjusting the edge face position and applying a semicircular port can strengthen the energy extracted from the edge face. This appears to be caused by changing the positional relationship between the standing wave mode and the edge face. Furthermore, the OLW‐W1 structure proposed in this report can achieve higher output extraction efficiency than the conventional OLW. The transmittance is enhanced by changing the structure near the edge face because this improves the matching of light speed in different media.
{"title":"Improvement of Output Extraction Efficiency by Optimizing Edge Structure of Circular Defect in Photonic Crystal Laser","authors":"Yuki Adachi, Issei Sada, M. Morifuji, H. Kajii, Akihiro Maruta, Masahiko Kondow","doi":"10.1002/pssa.202300579","DOIUrl":"https://doi.org/10.1002/pssa.202300579","url":null,"abstract":"We aim to achieve wavelength division multiplexing with a circular defect in two‐dimensional photonic crystal (CirD) laser that has an orthogonal lattice waveguide (OLW). In a simulation, we calculate the output extraction efficiency to discover a structure in which stronger optical output can be extracted for the CirD laser with OLW. Consequently, adjusting the edge face position and applying a semicircular port can strengthen the energy extracted from the edge face. This appears to be caused by changing the positional relationship between the standing wave mode and the edge face. Furthermore, the OLW‐W1 structure proposed in this report can achieve higher output extraction efficiency than the conventional OLW. The transmittance is enhanced by changing the structure near the edge face because this improves the matching of light speed in different media.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":" 434","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139617806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Perovskite solar cells (PSCs) with hybrid halide perovskite playing the role of photon‐harvesting materials have recently made strides in efficiency that have put them in the spotlight of solar cell research. Though PSCs are capable of exhibiting favorable photoconversion capabilities, they have not yet been commercialized as they are unstable in typical operating environments, especially for longer‐term usage. The mechanisms by which PSCs degrade, along with the methods to enhance their conversion efficiency, are studied, which, in turn, helps develop effective solutions to the degradation problem and increase the stability of the device architecture. A broad collection of theoretical and experimental analysis on stability of PSCs is available. In this article, a strategic review on the main challenges in attaining superior efficiency for PSCs along with the methods to overcome their efficiency limit is included providing emphasis to various degradation mechanisms of perovskite structures followed by a detailed examination of various factors impacting stability of PSCs as a whole. The performance and stability of devices can be improved by means of several methods including compositional engineering, interfacial engineering, device encapsulation, etc. The strategies that can be used to improve PSCs’ long‐term stability while ensuring cost‐effective device manufacture are covered here.
{"title":"Charting New Horizons: Unrivalled Efficiency and Stability in Perovskite Solar Cells","authors":"Deepthi Jayan Koodali","doi":"10.1002/pssa.202300782","DOIUrl":"https://doi.org/10.1002/pssa.202300782","url":null,"abstract":"Perovskite solar cells (PSCs) with hybrid halide perovskite playing the role of photon‐harvesting materials have recently made strides in efficiency that have put them in the spotlight of solar cell research. Though PSCs are capable of exhibiting favorable photoconversion capabilities, they have not yet been commercialized as they are unstable in typical operating environments, especially for longer‐term usage. The mechanisms by which PSCs degrade, along with the methods to enhance their conversion efficiency, are studied, which, in turn, helps develop effective solutions to the degradation problem and increase the stability of the device architecture. A broad collection of theoretical and experimental analysis on stability of PSCs is available. In this article, a strategic review on the main challenges in attaining superior efficiency for PSCs along with the methods to overcome their efficiency limit is included providing emphasis to various degradation mechanisms of perovskite structures followed by a detailed examination of various factors impacting stability of PSCs as a whole. The performance and stability of devices can be improved by means of several methods including compositional engineering, interfacial engineering, device encapsulation, etc. The strategies that can be used to improve PSCs’ long‐term stability while ensuring cost‐effective device manufacture are covered here.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":" 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139620390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morten Bertz, M. Schöning, Denise Molinnus, Takayuki Homma
To gain insight on chemical sterilization processes, the influence of temperature (up to 70 °C), intense green light, and hydrogen peroxide (H2O2) concentration (up to 30% in aqueous solution) on microbial spore inactivation is evaluated by in‐situ Raman spectroscopy with an optical trap. Bacillus atrophaeus is utilized as a model organism. Individual spores are isolated and their chemical makeup is monitored under dynamically changing conditions (temperature, light, and H2O2 concentration) to mimic industrially relevant process parameters for sterilization in the field of aseptic food processing. While isolated spores in water are highly stable, even at elevated temperatures of 70 °C, exposure to H2O2 leads to a loss of spore integrity characterized by the release of the key spore biomarker dipicolinic acid (DPA) in a concentration‐dependent manner, which indicates damage to the inner membrane of the spore. Intensive light or heat, both of which accelerate the decomposition of H2O2 into reactive oxygen species (ROS), drastically shorten the spore lifetime, suggesting the formation of ROS as a rate‐limiting step during sterilization. It is concluded that Raman spectroscopy can deliver mechanistic insight into the mode of action of H2O2‐based sterilization and reveal the individual contributions of different sterilization methods acting in tandem.
{"title":"Influence of Temperature, Light, and H2O2 Concentration on Microbial Spore Inactivation: In‐Situ Raman Spectroscopy Combined with Optical Trapping","authors":"Morten Bertz, M. Schöning, Denise Molinnus, Takayuki Homma","doi":"10.1002/pssa.202300866","DOIUrl":"https://doi.org/10.1002/pssa.202300866","url":null,"abstract":"To gain insight on chemical sterilization processes, the influence of temperature (up to 70 °C), intense green light, and hydrogen peroxide (H2O2) concentration (up to 30% in aqueous solution) on microbial spore inactivation is evaluated by in‐situ Raman spectroscopy with an optical trap. Bacillus atrophaeus is utilized as a model organism. Individual spores are isolated and their chemical makeup is monitored under dynamically changing conditions (temperature, light, and H2O2 concentration) to mimic industrially relevant process parameters for sterilization in the field of aseptic food processing. While isolated spores in water are highly stable, even at elevated temperatures of 70 °C, exposure to H2O2 leads to a loss of spore integrity characterized by the release of the key spore biomarker dipicolinic acid (DPA) in a concentration‐dependent manner, which indicates damage to the inner membrane of the spore. Intensive light or heat, both of which accelerate the decomposition of H2O2 into reactive oxygen species (ROS), drastically shorten the spore lifetime, suggesting the formation of ROS as a rate‐limiting step during sterilization. It is concluded that Raman spectroscopy can deliver mechanistic insight into the mode of action of H2O2‐based sterilization and reveal the individual contributions of different sterilization methods acting in tandem.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":" 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139619718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal–semiconductor–metal (MSM) varactor diodes are integrated with a THz fishnet metamaterial with its resonance frequency in the terahertz (THz) frequency range. The electrically tunable capacitance enabled by MSM varactor diodes can shift the resonance frequency of the THz fishnet metamaterial and modulate the amplitude of transmitted THz waves. Conventional MSM varactor diodes can be represented by an equivalent circuit consisting of the series‐connected resistance and capacitance. When the frequency increases, the kinetic inductance associated with the two‐dimensional electron gas (2DEG) becomes significant in the THz frequency range. A very large resonance frequency shift as large as 0.57 THz is obtained due to the effect of the kinetic inductance change as well as the capacitance change in the THz metamaterial based on the fishnet structures. The fabricated THz fishnet metamaterial integrated with the MSM‐2DEG varactor diodes exhibits a modulation depth of 54.7% and an insertion loss of 3.32 dB at 0.66 THz.
{"title":"Active Terahertz Metamaterials Integrated with Metal–Semiconductor–Metal Varactor Diodes for Amplitude Modulation","authors":"Gyejung Lee, Ji Hyun Hwang, Jae‐Hyung Jang","doi":"10.1002/pssa.202300655","DOIUrl":"https://doi.org/10.1002/pssa.202300655","url":null,"abstract":"Metal–semiconductor–metal (MSM) varactor diodes are integrated with a THz fishnet metamaterial with its resonance frequency in the terahertz (THz) frequency range. The electrically tunable capacitance enabled by MSM varactor diodes can shift the resonance frequency of the THz fishnet metamaterial and modulate the amplitude of transmitted THz waves. Conventional MSM varactor diodes can be represented by an equivalent circuit consisting of the series‐connected resistance and capacitance. When the frequency increases, the kinetic inductance associated with the two‐dimensional electron gas (2DEG) becomes significant in the THz frequency range. A very large resonance frequency shift as large as 0.57 THz is obtained due to the effect of the kinetic inductance change as well as the capacitance change in the THz metamaterial based on the fishnet structures. The fabricated THz fishnet metamaterial integrated with the MSM‐2DEG varactor diodes exhibits a modulation depth of 54.7% and an insertion loss of 3.32 dB at 0.66 THz.","PeriodicalId":506741,"journal":{"name":"physica status solidi (a)","volume":"23 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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