We calculate a universal shift in work function of 59.4 meV per decade of dopant concentration change that applies to all doped semiconductors and from this use Monte Carlo simulations to simulate the resulting change in secondary electron yield for doped GaAs. We then compare experimental images of doped GaAs layers from scanning electron microscopy and conductive atomic force microscopy. Kelvin probe force microscopy allows to directly measure and map local work function changes, but values measured are often smaller, typically only around half, of what theory predicts for perfectly clean surfaces.
{"title":"Towards quantification of doping in gallium arsenide nanostructures by low-energy scanning electron microscopy and conductive atomic force microscopy","authors":"Ran Guo, Thomas Walther","doi":"10.1111/jmi.13263","DOIUrl":"10.1111/jmi.13263","url":null,"abstract":"<p>We calculate a universal shift in work function of 59.4 meV per decade of dopant concentration change that applies to all doped semiconductors and from this use Monte Carlo simulations to simulate the resulting change in secondary electron yield for doped GaAs. We then compare experimental images of doped GaAs layers from scanning electron microscopy and conductive atomic force microscopy. Kelvin probe force microscopy allows to directly measure and map local work function changes, but values measured are often smaller, typically only around half, of what theory predicts for perfectly clean surfaces.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmi.13263","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139484746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The utility of fluorescence lifetime imaging microscopy (FLIM) for identifying bacteria in complex mineral matrices was investigated. Baseline signals from unlabelled Bacillus subtilis and Euglena gracilis, and Bacillus subtilis labelled with SYTO 9 were obtained using two-photon excitation at 730, 750 and 800 nm, identifying characteristic lifetimes of photosynthetic pigments, unpigmented cellular autofluorescence, and SYTO 9. Labelled and unlabelled B. subtilis were seeded onto marble and gypsum samples containing endolithic photosynthetic cyanobacteria and the ability to distinguish cells from mineral autofluorescence and nonspecific dye staining was examined in parallel with ordinary multichannel confocal imaging. It was found that FLIM enabled discrimination of SYTO 9 labelled cells from background, but that the lifetime of SYTO 9 was shorter in cells on minerals than in pure culture under our conditions. Photosynthetic microorganisms were easily observed using both FLIM and confocal. Unlabelled, nonpigmented bacteria showed weak signals that were difficult to distinguish from background when minerals were present, though cellular autofluorescence consistent with NAD(P)H could be seen in pure cultures, and phasor analysis permitted detection on rocks. Gypsum and marble samples showed similar autofluorescence profiles, with little autofluorescence in the yellow-to-red range. Lifetime or time-gated imaging may prove a useful tool for environmental microbiology.
LAY DESCRIPTION: The standard method of bacterial enumeration is to label the cells with a fluorescent dye and count them under high-power fluorescence microscopy. However, this can be difficult when the cells are embedded in soil and rock due to fluorescence from the surrounding minerals and dye binding to ambiguous features of the substrate. The use of fluorescence lifetime imaging (FLIM) can disambiguate these signals and allow for improved detection of bacteria in environmental samples.
{"title":"The use of fluorescence lifetime imaging (FLIM) for in situ microbial detection in complex mineral substrates","authors":"Yekaterina Chmykh, Jay L. Nadeau","doi":"10.1111/jmi.13264","DOIUrl":"10.1111/jmi.13264","url":null,"abstract":"<p>The utility of fluorescence lifetime imaging microscopy (FLIM) for identifying bacteria in complex mineral matrices was investigated. Baseline signals from unlabelled <i>Bacillus subtilis</i> and <i>Euglena gracilis</i>, and <i>Bacillus subtilis</i> labelled with SYTO 9 were obtained using two-photon excitation at 730, 750 and 800 nm, identifying characteristic lifetimes of photosynthetic pigments, unpigmented cellular autofluorescence, and SYTO 9. Labelled and unlabelled <i>B. subtilis</i> were seeded onto marble and gypsum samples containing endolithic photosynthetic cyanobacteria and the ability to distinguish cells from mineral autofluorescence and nonspecific dye staining was examined in parallel with ordinary multichannel confocal imaging. It was found that FLIM enabled discrimination of SYTO 9 labelled cells from background, but that the lifetime of SYTO 9 was shorter in cells on minerals than in pure culture under our conditions. Photosynthetic microorganisms were easily observed using both FLIM and confocal. Unlabelled, nonpigmented bacteria showed weak signals that were difficult to distinguish from background when minerals were present, though cellular autofluorescence consistent with NAD(P)H could be seen in pure cultures, and phasor analysis permitted detection on rocks. Gypsum and marble samples showed similar autofluorescence profiles, with little autofluorescence in the yellow-to-red range. Lifetime or time-gated imaging may prove a useful tool for environmental microbiology.</p><p><b>LAY DESCRIPTION</b>: The standard method of bacterial enumeration is to label the cells with a fluorescent dye and count them under high-power fluorescence microscopy. However, this can be difficult when the cells are embedded in soil and rock due to fluorescence from the surrounding minerals and dye binding to ambiguous features of the substrate. The use of fluorescence lifetime imaging (FLIM) can disambiguate these signals and allow for improved detection of bacteria in environmental samples.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmi.13264","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139478453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Behnam Esmaeilzadeh, Muhammad Touqeer, Liu Junwei, Shaofeng Zheng, Tao Geng, Yubin Hou, Qingyou Lu
We present the design and performance of a novel scanning tunnelling microscope (STM) operating in a cryogen-free superconducting magnet. Our home-built STM head is compact (51.5 mm long and 20 mm in diameter) and has a single arm that provides complete openness in the scanning area between the tip and sample. The STM head consists of two piezoelectric tubes (PTs), a piezoelectric scanning tube (PST) mounted on a well-polished zirconia shaft, and a large PT housed in a sapphire tube called the motor tube. The main body of the STM head is made of tantalum. In this design, we fixed the sapphire tube to the frame with screws so that the tube's position can be changed quickly. To analyse the stiffness of the STM head unit, we identified the lowest eigenfrequencies with 3 and 4 kHz in the bending modes, 8 kHz in a torsional mode, and 9 kHz in a longitudinal mode by finite element analysis, and also measured the low drift rates in the X–Y plane and in the Z direction. The high performance of the home-built STM was demonstrated by images of the hexagonal graphite lattice at 300 K and in a sweeping magnetic field from 0 T to 9 T. Our results confirm the high stability, vibration resistance, insensitivity to high magnetic fields and the application potential of our newly developed STM for the investigation of low-frequency systems with high static support stiffness in physics, chemistry, material and biological sciences.
{"title":"Atomic resolution imaging using a novel, compact and stiff scanning tunnelling microscope in cryogen-free superconducting magnet","authors":"Behnam Esmaeilzadeh, Muhammad Touqeer, Liu Junwei, Shaofeng Zheng, Tao Geng, Yubin Hou, Qingyou Lu","doi":"10.1111/jmi.13262","DOIUrl":"10.1111/jmi.13262","url":null,"abstract":"<p>We present the design and performance of a novel scanning tunnelling microscope (STM) operating in a cryogen-free superconducting magnet. Our home-built STM head is compact (51.5 mm long and 20 mm in diameter) and has a single arm that provides complete openness in the scanning area between the tip and sample. The STM head consists of two piezoelectric tubes (PTs), a piezoelectric scanning tube (PST) mounted on a well-polished zirconia shaft, and a large PT housed in a sapphire tube called the motor tube. The main body of the STM head is made of tantalum. In this design, we fixed the sapphire tube to the frame with screws so that the tube's position can be changed quickly. To analyse the stiffness of the STM head unit, we identified the lowest eigenfrequencies with 3 and 4 kHz in the bending modes, 8 kHz in a torsional mode, and 9 kHz in a longitudinal mode by finite element analysis, and also measured the low drift rates in the <i>X</i>–<i>Y</i> plane and in the <i>Z</i> direction. The high performance of the home-built STM was demonstrated by images of the hexagonal graphite lattice at 300 K and in a sweeping magnetic field from 0 T to 9 T. Our results confirm the high stability, vibration resistance, insensitivity to high magnetic fields and the application potential of our newly developed STM for the investigation of low-frequency systems with high static support stiffness in physics, chemistry, material and biological sciences.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139466815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The most crucial task of petroleum geology is to explore oil and gas reservoirs in the deep underground. As one of the analysis techniques in petroleum geological research, rock thin section identification method includes particle segmentation, which is one of the key steps. A conventional sandstone thin section image typically contains hundreds of mineral particles with blurred boundaries and complex microstructures inside the particles. Moreover, the complex lithology and low porosity of tight sandstone make traditional image segmentation methods unsuitable for solving the complex thin section segmentation problems. This paper combines petrology and image processing technologies. First, polarised sequence images are aligned, and then the images are transformed to the HSV colour space to extract pores. Second, particles are extracted according to their extinction characteristics. Last, a concavity and corner detection matching method is used to process the extracted particles, thereby completing the segmentation of sandstone thin section images. The experimental results show that our proposed method can more accurately fit the boundaries of mineral particles in sandstone images than existing image segmentation methods. Additionally, when applied in actual production scenarios, our method exhibits excellent performance, greatly improving thin section identification efficiency and significantly assisting experts in identification.
{"title":"A multiangle polarised imaging-based method for thin section segmentation","authors":"Yan Chen, Yu Yi, Yongfang Dai, Xiangchao Shi","doi":"10.1111/jmi.13261","DOIUrl":"10.1111/jmi.13261","url":null,"abstract":"<p>The most crucial task of petroleum geology is to explore oil and gas reservoirs in the deep underground. As one of the analysis techniques in petroleum geological research, rock thin section identification method includes particle segmentation, which is one of the key steps. A conventional sandstone thin section image typically contains hundreds of mineral particles with blurred boundaries and complex microstructures inside the particles. Moreover, the complex lithology and low porosity of tight sandstone make traditional image segmentation methods unsuitable for solving the complex thin section segmentation problems. This paper combines petrology and image processing technologies. First, polarised sequence images are aligned, and then the images are transformed to the HSV colour space to extract pores. Second, particles are extracted according to their extinction characteristics. Last, a concavity and corner detection matching method is used to process the extracted particles, thereby completing the segmentation of sandstone thin section images. The experimental results show that our proposed method can more accurately fit the boundaries of mineral particles in sandstone images than existing image segmentation methods. Additionally, when applied in actual production scenarios, our method exhibits excellent performance, greatly improving thin section identification efficiency and significantly assisting experts in identification.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139466814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantitative phase imaging (QPI) is a powerful tool for label-free visualisation of living cells. Here, we compare two QPI microscopes – the Telight Q-Phase microscope and the Nanolive 3D Cell Explorer-fluo microscope. Both systems provide unbiased information about cell morphology, such as individual cell dry mass, perimeter and area. The Q-Phase microscope uses artefact-free, coherence-controlled holographic imaging technology to visualise cells in real time with minimal phototoxicity. The 3D Cell Explorer-fluo employs laser-based holotomography to reconstruct 3D images of living cells, visualising their internal structures and dynamics. Here, we analysed the strengths and limitations of both microscopes when examining two morphologically distinct cell lines – the cuboidal epithelial MDCK cells which form multicellular clusters and solitary growing Rat2 fibroblasts. We focus mainly on the ability of the devices to generate images suitable for single-cell segmentation by the built-in software, and we discuss the segmentation results and quantitative data generated from the segmented images. We show that both microscopes offer slightly different advantages, and the choice between them depends on the specific requirements and goals of the user.
{"title":"Comparison of holotomographic microscopy and coherence-controlled holographic microscopy","authors":"Vera Chvalova, Tomas Vomastek, Tomas Grousl","doi":"10.1111/jmi.13260","DOIUrl":"10.1111/jmi.13260","url":null,"abstract":"<p>Quantitative phase imaging (QPI) is a powerful tool for label-free visualisation of living cells. Here, we compare two QPI microscopes – the Telight Q-Phase microscope and the Nanolive 3D Cell Explorer-fluo microscope. Both systems provide unbiased information about cell morphology, such as individual cell dry mass, perimeter and area. The Q-Phase microscope uses artefact-free, coherence-controlled holographic imaging technology to visualise cells in real time with minimal phototoxicity. The 3D Cell Explorer-fluo employs laser-based holotomography to reconstruct 3D images of living cells, visualising their internal structures and dynamics. Here, we analysed the strengths and limitations of both microscopes when examining two morphologically distinct cell lines – the cuboidal epithelial MDCK cells which form multicellular clusters and solitary growing Rat2 fibroblasts. We focus mainly on the ability of the devices to generate images suitable for single-cell segmentation by the built-in software, and we discuss the segmentation results and quantitative data generated from the segmented images. We show that both microscopes offer slightly different advantages, and the choice between them depends on the specific requirements and goals of the user.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139403306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ellen Verwee, Davy Van de Walle, Michiel De Bruyne, Esther Mienis, Mirna Sekulic, Peter Chaerle, Wim Vyverman, Imogen Foubert, Koen Dewettinck
In this study, transmission electron microscopy (TEM) and cryo-scanning electron microscopy (cryo-SEM) were evaluated for their ability to detect lipid bodies in microalgae. To do so, Phaeodactylum tricornutum and Nannochloropsis oculata cells were harvested in both the mid-exponential and early stationary growth phase. Two different cryo-SEM cutting methods were compared: cryo-planing and freeze-fracturing. The results showed that, despite the longer preparation time, TEM visualisation preceded by cryo-immobilisation allows a clear detection of lipid bodies and is preferable to cryo-SEM. Using freeze-fracturing, lipid bodies were rarely detected. This was only feasible if crystalline layers in the internal structure, most likely related to sterol esters or di-saturated triacylglycerols, were revealed. Furthermore, lipid bodies could not be detected using cryo-planing. Cryo-SEM is also not the preferred technique to recognise other organelles besides lipid bodies, yet it did reveal chloroplasts in both species and filament-containing organelles in cryo-planed Nannochloropsis oculata samples.
本研究评估了透射电子显微镜(TEM)和低温扫描电子显微镜(Cryo-SEM)检测微藻脂质体的能力。为此,研究人员采集了处于旺盛生长中期和静止生长早期的 Phaeodactylum tricornutum 和 Nannochloropsis oculata 细胞。比较了两种不同的低温扫描电镜切割方法:低温平整和冷冻切割。结果表明,尽管制备时间较长,但在冷冻固定之前进行 TEM 观察可清晰地检测脂质体,比冷冻-SEM 更为可取。使用冷冻断裂法很少能检测到脂质体。只有当内部结构中的结晶层(很可能与固醇酯或二饱和三酰甘油有关)被揭示出来时,才能检测到脂质体。此外,冷冻平铺法也无法检测到脂质体。低温扫描电镜也不是识别脂质体以外的其他细胞器的首选技术,但它确实发现了两个物种中的叶绿体,以及低温刨平的 Nannochloropsis oculata 样品中的含丝细胞器。本文受版权保护。版权所有 脂质体是一种细胞器,在细胞内起到储存脂质的作用。微藻类积累的脂质可占其干重的 50%以上。这些脂质可用于生产生物燃料和食品。某些微藻类生长速度快、产量高,是一种有趣的替代脂质来源。当细胞在营养限制等不利条件下生长时,微藻中的脂质含量会增加。本研究的目的是比较先进的显微镜技术,以观察两种不同微藻中的脂质体。第一种技术是透射电子显微镜(TEM),即在观察前对样品进行高压冷冻、冷冻替代并切成薄片。第二种技术是低温扫描电子显微镜(cryo-SEM),首先采用两种不同的切割方法来显示样品的内部结构。样品被快速冷冻后,要么被粗暴地折断(冷冻折断),要么被锋利的刀切割,以获得一个平整的表面(冷冻平整)。对每种微藻的生长中期和早期静止期细胞进行了检测,预计后者的脂质体数量更多。结果表明,先用 TEM 观察,然后再冷冻固定,可以检测到脂质体,尽管制备时间较长,但比冷冻-SEM 更优。使用冷冻断裂法只能偶尔检测到几个脂质体,因为断裂面需要穿过脂质体,显示内部结构(层),这对于脂质体的识别是必要的。冷冻平铺技术对检测这些样本中的脂质体没有帮助,因为这种技术会导致细胞表面变平。此外,TEM 能显示最多的其他细胞器,而冷冻扫描电镜只能显示叶绿体和含丝细胞器。我们的发现有助于其他研究人员选择合适的电子显微镜技术来观察生物样本中的脂质体或食品基质的微观结构。
{"title":"Visualisation of microalgal lipid bodies through electron microscopy","authors":"Ellen Verwee, Davy Van de Walle, Michiel De Bruyne, Esther Mienis, Mirna Sekulic, Peter Chaerle, Wim Vyverman, Imogen Foubert, Koen Dewettinck","doi":"10.1111/jmi.13259","DOIUrl":"10.1111/jmi.13259","url":null,"abstract":"<p>In this study, transmission electron microscopy (TEM) and cryo-scanning electron microscopy (cryo-SEM) were evaluated for their ability to detect lipid bodies in microalgae. To do so, <i>Phaeodactylum tricornutum</i> and <i>Nannochloropsis oculata</i> cells were harvested in both the mid-exponential and early stationary growth phase. Two different cryo-SEM cutting methods were compared: cryo-planing and freeze-fracturing. The results showed that, despite the longer preparation time, TEM visualisation preceded by cryo-immobilisation allows a clear detection of lipid bodies and is preferable to cryo-SEM. Using freeze-fracturing, lipid bodies were rarely detected. This was only feasible if crystalline layers in the internal structure, most likely related to sterol esters or di-saturated triacylglycerols, were revealed. Furthermore, lipid bodies could not be detected using cryo-planing. Cryo-SEM is also not the preferred technique to recognise other organelles besides lipid bodies, yet it did reveal chloroplasts in both species and filament-containing organelles in cryo-planed <i>Nannochloropsis oculata</i> samples.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139040123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Correlative super-resolution microscopy has the potential to accurately visualize and validate new biological structures past the diffraction limit. However, combining different super-resolution modalities, such as deterministic stimulated emission depletion (STED) and stochastic single-molecule localization microscopy (SMLM), is a challenging endeavour. For correlative STED and SMLM, the following poses a significant challenge: (1) the photobleaching of the fluorophores in STED; (2) the subsequent reactivation of the fluorophores for SMLM and (3) finding the right fluorochrome and imaging buffer for both imaging modalities. Here, we highlight how the deep ultraviolet (DBUE) wavelengths of the Mercury (Hg) arc lamp can help recover STED bleaching and allow for the reactivation of single molecules for SMLM imaging. We also show that Alexa Fluor 594 and the commercially available Prolong Diamond to be excellent fluorophores and imaging media for correlative STED and SMLM.
相关超分辨率显微镜有可能准确地观察和验证超越衍射极限的新生物结构。然而,将不同的超分辨率模式(如确定性受激发射损耗(STED)和随机单分子定位显微镜(SMLM))结合起来是一项具有挑战性的工作。对于相关 STED 和 SMLM,以下几点构成了重大挑战:(1) STED 中荧光团的光漂白;(2) SMLM 中荧光团的后续重新激活;(3) 为两种成像模式找到合适的荧光色素和成像缓冲液。在此,我们重点介绍汞(Hg)弧光灯的深紫外(DBUE)波长如何帮助恢复 STED 漂白,并使单个分子重新活化,用于 SMLM 成像。我们还表明,Alexa Fluor 594 和市售的 Prolong Diamond 是用于 STED 和 SMLM 关联成像的优秀荧光团和成像介质。本文受版权保护。保留所有权利。
{"title":"Correlative super-resolution microscopy with deep UV reactivation.","authors":"Kirti Prakash","doi":"10.1111/jmi.13258","DOIUrl":"10.1111/jmi.13258","url":null,"abstract":"<p><p>Correlative super-resolution microscopy has the potential to accurately visualize and validate new biological structures past the diffraction limit. However, combining different super-resolution modalities, such as deterministic stimulated emission depletion (STED) and stochastic single-molecule localization microscopy (SMLM), is a challenging endeavour. For correlative STED and SMLM, the following poses a significant challenge: (1) the photobleaching of the fluorophores in STED; (2) the subsequent reactivation of the fluorophores for SMLM and (3) finding the right fluorochrome and imaging buffer for both imaging modalities. Here, we highlight how the deep ultraviolet (DBUE) wavelengths of the Mercury (Hg) arc lamp can help recover STED bleaching and allow for the reactivation of single molecules for SMLM imaging. We also show that Alexa Fluor 594 and the commercially available Prolong Diamond to be excellent fluorophores and imaging media for correlative STED and SMLM.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139037825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuo Liu, Jiawei Dong, Zhenyu Ma, Wenyu Hu, Yong Deng, Yuechun Shi, Xiaoyi Wang, Yang Qiu, Thomas Walther
Gallium ion (Ga+) beam damage induced indium (In) precipitation in indium gallium arsenide (InGaAs)/indium aluminium arsenide (InAlAs) multiple quantum wells and its corresponding evolution under electron beam irradiation was investigated by valence electron energy loss spectroscopy (VEELS) and high-angle annular dark-field imaging (HAADF) in scanning transmission electron microscopy (STEM). Compared with argon ion milling for sample preparation, the heavier projectiles of Ga+ ions pose a risk to trigger In formation in the form of tiny metallic In clusters. These are shown to be sensitive to electron irradiation and can increase in number and size under the electron beam, deteriorating the structure. Our finding reveals the potential risk of formation of In clusters during focused ion beam (FIB) preparation of InGaAs/InAlAs quantum well samples and their subsequent growth under STEM-HAADF imaging, where initially invisible In clusters of a few atoms can move and swell during electron beam exposure.
通过价电子能损耗谱(VEELS)和扫描透射电子显微镜(STEM)中的高角度环形暗场成像(HAADF),研究了镓离子(Ga+)束损伤诱导砷化铟(InGaAs)/砷化铟铝(InAlAs)多量子阱中的铟(In)析出及其在电子束辐照下的相应演变。与氩离子研磨制备样品相比,较重的 Ga+ 离子射弹有可能以微小金属铟簇的形式引发铟的形成。事实证明,这些微小金属铟簇对电子辐照非常敏感,在电子束的作用下,它们的数量和尺寸都会增加,从而导致结构恶化。我们的发现揭示了在聚焦离子束(FIB)制备 InGaAs/InAlAs 量子阱样品及其随后在 STEM-HAADF 成像下的生长过程中形成 In 簇的潜在风险。布局描述 本文通过价电子能损耗谱(VEELs)、能量色散 X 射线光谱(EDXs)和基于探针像差校正扫描透射电子显微镜的高角度环形暗场(HAADF)成像技术,研究了电子束辐照下 InGaAs/InAlAs 多量子阱中 Ga+ 植入诱导 In 沉淀的演变过程。与 Ar+ 离子轰击不同,聚焦的 Ga+ 离子射弹能够触发 InGaAs/InAlAs 多量子阱中的 In 间隙团聚,从而形成金属 In 沉淀。之后,通过在铟析出区域进行广泛的电子束光栅化,电子辐照时间的增加会导致铟簇尺寸的明显膨胀。特别是在含有几个原子的铟析出物的区域,原子图像中看不到铟簇的形态。持续的电子辐照可能会促进铟的团聚,从而使铟沉淀的结构在 HAADF 图像中得以解析。我们的发现揭示了在聚焦 Ga+ 离子束轰击 InGaAs/InAlAs 半导体过程中形成铟沉淀的潜在风险,以及随后在电子束光栅化作用下铟团聚的演变过程。这些发现强调了在使用 TEM 研究 FIB 制备的 In 基 III-V 量子阱试样(即使是 In(Ga,Al)As 系统)时需要谨慎,因为最初形成的富 In 簇非常小,在一段时间内仍不可见。本文受版权保护。保留所有权利。
{"title":"The evolution of indium precipitation in gallium focused ion beam prepared samples of InGaAs/InAlAs quantum wells under electron beam irradiation","authors":"Shuo Liu, Jiawei Dong, Zhenyu Ma, Wenyu Hu, Yong Deng, Yuechun Shi, Xiaoyi Wang, Yang Qiu, Thomas Walther","doi":"10.1111/jmi.13251","DOIUrl":"10.1111/jmi.13251","url":null,"abstract":"<p>Gallium ion (Ga<sup>+</sup>) beam damage induced indium (In) precipitation in indium gallium arsenide (InGaAs)/indium aluminium arsenide (InAlAs) multiple quantum wells and its corresponding evolution under electron beam irradiation was investigated by valence electron energy loss spectroscopy (VEELS) and high-angle annular dark-field imaging (HAADF) in scanning transmission electron microscopy (STEM). Compared with argon ion milling for sample preparation, the heavier projectiles of Ga<sup>+</sup> ions pose a risk to trigger In formation in the form of tiny metallic In clusters. These are shown to be sensitive to electron irradiation and can increase in number and size under the electron beam, deteriorating the structure. Our finding reveals the potential risk of formation of In clusters during focused ion beam (FIB) preparation of InGaAs/InAlAs quantum well samples and their subsequent growth under STEM-HAADF imaging, where initially invisible In clusters of a few atoms can move and swell during electron beam exposure.</p>","PeriodicalId":16484,"journal":{"name":"Journal of microscopy","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138802144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}