TY - JOUR
AU - Takeguchi, Masaki
AB - Abstract Liquid cell transmission electron microscopy (LCTEM) enables imaging of dynamic processes in liquid with high spatial and temporal resolution. The widely used liquid cell (LC) consists of two stacking microchips with a thin wet sample sandwiched between them. The vertically overlapped electron-transparent membrane windows on the microchips provide passage for the electron beam. However, microchips with imprecise dimensions usually cause poor alignment of the windows and difficulty in acquiring high-quality images. In this study, we developed a new and efficient microchip fabrication process for LCTEM with a large viewing area (180 µm × 40 µm) and evaluated the resultant LC. The new positioning reference marks on the surface of the Si wafer dramatically improve the precision of dicing the wafer, making it possible to accurately align the windows on two stacking microchips. The precise alignment led to a liquid thickness of 125.6 nm close to the edge of the viewing area. The performance of our LC was demonstrated by in situ transmission electron microscopy imaging of the dynamic motions of 2-nm Pt particles. This versatile and cost-effective microchip production method can be used to fabricate other types of microchips for in situ electron microscopy. liquid cell, microchip, alignment, position reference mark, transmission electron microscopy, in situ Introduction Liquid cell or liquid-phase transmission electron microscopy (LCTEM or LPTEM) is a powerful tool that enables us to in situ observe dynamic processes in liquid [1,2]. The liquid cell (LC) removes the need for a transmission electron microscopy (TEM) sample to be dry and solid. High spatial- and temporal-resolution images have been obtained with LCTEM [3]. More functional LCs have also been realized by incorporating electrodes and heating elements [4–6]. The typical LC has a sandwich architecture consisting of two stacking microchips each supporting a freestanding electron-transparent membrane. The membranes are commonly made of low-stress silicon nitride (SiNx). The SiNx membranes on the two microchips require precise alignment during assembly to provide a large viewing area. Window alignment is important for obtaining a high-quality image. Because of the significant pressure difference between the interior of the LC (approximately atmospheric pressure) and high vacuum of a TEM column (∼10−5 Pa at the sample position), the SiNx membranes bulge toward the TEM vacuum [7,8]. The deformation is most severe at the center of the membrane and gradually decreases toward the edge. Accordingly, the electron scattering is weaker at the edge and image quality improves. Good alignment allows the edge of the two membranes to overlap as closely as possible, and the liquid is thinnest at the edge area. However, precise alignment of the two membrane windows on the stacking microchips is challenging in the sandwich LC [9]. Because the SiNx membranes are small (typically 50 µm × 200 µm), it is impractical to directly align the two windows. The alignment is always done by manipulating the two stacking microchips. Huang et al. developed a self-aligned LC consisting of two geometrically complementary counterparts, in which the bottom microchip had a tip-truncated pyramidal cavity and the upper chip had a geometry fitting the cavity [10]. Leenheer et al. aligned the upper and lower windows using two spherical micro-ball lenses placed into the pyramidal alignment holes etched on the upper and lower microchips [11]. Ring and De Jonge used a dicing machine to produce microchips with straight edges and sufficiently accurate dimensions. The alignment was completed simply using the alignment poles of the pocket holding the stacking microchips [12]. The window alignment is fundamentally linked to the microchip production procedure. Microchips are commonly produced by cleaving wafers along a specific crystal direction such as the <110> direction on a {100} wafer. Manual separation cannot give chips with accurate dimensions. Kim et al. prepared microchips through manual snapping. The edges of their chips were not straight, and consequently, the dimensions were inaccurate [13]. This likely made alignment difficult. The microchips are usually separated along V grooves etched on the side (denoted as the top side) where the SiNx membrane windows are supported [14,15]. However, the patterns of the grooves and windows are defined on different sides, i.e. a groove pattern on the top side but a window pattern on the bottom side. The groove is formed by partially etching the wafer. The etching proceeds from the top side toward the bottom side. However, the membrane formation has a reverse etching direction and requires complete etching of the Si bulk. The two patterns should be accurately aligned so that the window is at desired positions on a microchip (commonly at a chip’s center) after the separation. In typical production, they are made in separate processes, i.e. first for the windows and then for the grooves. The method of the pattern alignment on the two sides of the wafer is rarely mentioned in the literature [7,8,11–14]. Furthermore, the processes of creating windows and grooves involve repeated lithography and etching steps. These increase the risk of membrane damage during production and raise the cost of individual chips. In this work, we developed a new and efficient microchip production process that overcomes the alignment challenges in assembling an LC and evaluated the resultant LC. A sandwich LC was assembled and incorporated into an originally designed LC holding device that could be mounted onto a TEM holder’s head. This was followed by in situ LCTEM observation of the dynamic motions of nanoscale Pt particles in water. Methods Figure 1 depicts the cross section of the fabricated sandwich LC. The LC consists of two Si microchips with the same dimensions. The thickness of the SiNx membrane is 50 nm. The thickness should be minimized to reduce electron scattering when the electron beam passes through the membrane. However, the membrane will suffer from stress caused by the outward deformation in the TEM’s high-vacuum environment, and therefore, the SiNx thickness should be sufficient to withstand the stress. We chose a 50-nm-thick SiNx membrane because it has been shown to be capable of surviving in high-vacuum conditions and causes negligible electron beam broadening [14,16]. In contrast, the area of the SiNx membrane should be maximized to allow as much of the enclosed sample as possible to be viewed. However, a large window will also easily deform and break during observation. The width of the window has been found to have a major effect on the deformation. A width of 50 µm has been discovered to be safe [14], and window deformation with this width is less significant. We chose the SiNx membrane area to be 50 µm × 300 µm. The spacer on the bottom chip is made of SiO2 and has a thickness of 50 nm. The sample is confined in the space defined by the spacers. Fig. 1. Open in new tabDownload slide Schematic of the cross section of the liquid cell. Not drawn to scale. Fig. 1. Open in new tabDownload slide Schematic of the cross section of the liquid cell. Not drawn to scale. The two stacking microchips were cut from one wafer rather than from two separate wafers. Fig. 2a and b are schematics of the top and bottom surfaces of a SiNx-coated Si wafer before dicing. Each chip has a freestanding electron-transparent SiNx membrane (labeled 1 in Fig. 2a) on its top surface. There are spacers (labeled 2 in Fig. 2a) on two columns of the microchips. The positioning reference marks (labeled 3 in Fig. 2a) are through holes and define the cutting paths along the vertical and horizontal dashed lines. The membrane windows and reference marks were created with anisotropic wet etching. Because the wafer is of the {100} type, tip-truncated pyramidal holes were formed after the etching as shown in Fig. 2b. The edges of the marks and windows were parallel to the <110> directions. The SiNx membranes at the window positions were maintained, while the SiNx membranes at the designed reference marks were removed. Fig. 2. Open in new tabDownload slide Top (a) and bottom (b) sides of a SiNx-coated {100} Si wafer before dicing. 1: membrane windows; 2: spacers; 3: positioning reference marks. Not drawn to scale. Fig. 2. Open in new tabDownload slide Top (a) and bottom (b) sides of a SiNx-coated {100} Si wafer before dicing. 1: membrane windows; 2: spacers; 3: positioning reference marks. Not drawn to scale. Figure 3 illustrates the steps for fabricating the microchips for the LC. Three-inch double-side polished SiNx-coated Si wafers were purchased from Silicon Valley Microelectronics (USA). The wafers had a <110> orientation flat. The 50-nm SiNx layer was deposited on the wafer via low-pressure chemical vapor deposition, and the layer had a super-low stress of ≤100 MPa. We called the side of the wafer on which the SiNx membrane windows were fabricated the ‘top’ and the other side the ‘bottom’. The top side was glued onto a Si-wafer substrate with polymethyl methacrylate (PMMA) to protect the SiNx layer against any possible damage during the patterning procedure. The bottom side faced upward and was spin-coated with photoresists (Fig. 3, step i). The patterns of the windows and positioning reference marks were defined on the surface with a high-speed maskless lithography system (NL-1000/NC2P, Nanosystem Solution, Japan) (Fig. 3, step ii). The edges of the individual window and positioning reference mark were parallel to the <110> direction of the wafer as depicted in Fig. 2a and b. To align the direction, the orientation flat of the wafer was used as the reference during the lithography. Although the wafer’s orientation flat typically had a deviation of ≤5° from the <110> direction [17], it was acceptable for our purpose. Fig. 3. Open in new tabDownload slide Schematic of the microchip production steps. Fig. 3. Open in new tabDownload slide Schematic of the microchip production steps. After the photolithography, the exposed photoresists were developed, and the exposed SiNx layer was eliminated with a reactive ion etcher (RIE) (MUC-21 ASE-SRE, Sumitomo Precision Products Co., Ltd., Japan) (Fig. 3, step iii). The etching depth must be controlled. Excessive RIE etching would result in an oversized window after the following potassium hydroxide (KOH) etching. The photoresists were removed using an 80°C n-methyl-2-pyrrolidone (NMP) bath. Because the PMMA was also soluble in the NMP, the wafer and the substrate were also simultaneously split. After the patterning procedures, the wafer was turned upside down and then soaked in a 90°C KOH aqueous solution for etching (Fig. 3, step iv). The bulk Si at the exposed regions was anisotropically etched. Tip-truncated pyramidal holes were finally formed at the etching regions. The suspended SiNx membranes at the designed positioning reference marks were cleared with an adhesive tape (Fig. 3, step v). To deposit the SiO2 spacers on the surface, the photoresists were again spin-coated and patterned with the maskless lithography system (Fig. 3, steps vi and vii). Because the through holes would not be covered by the photoresists, the openings of the positioning reference marks on the top surface could be seen with the optical microscope of the photolithography machine and were able to guide the patterning. After the photoresists were developed, the wafer was cleaned with oxygen plasma asher (PB-600, Yamato Scientific Co., Ltd., Japan), and the SiO2 spacers were deposited with an auto sputter deposition system (J Sputter, ULVAC, Japan) (Fig. 3, step viii). The deposited material did not cover the positioning reference marks. They were still maintained and clearly visible after the deposition. The wafer was cut with a dicing machine (DAD 323, Disco Co., Japan) (Fig. 3, step ix). The photoresists still covered the wafer to protect the ultrathin membrane from damage during the cutting. The thickness of the dicing saw was 50 µm. This thickness should be considered when designing the microchips. The openings of the positioning reference marks on the surface were clearly seen with the machine’s microscope. The dicing saw was set to cross the middle points of the opposite openings’ edges and traveled along the virtual dashed lines shown in Fig. 2a and b. After the photoresist removal, the two chips with and without spacers could be assembled to form a LC. The yield of the microchips through this method was 100%. Figure 4a shows the corner region of the microchip after the dicing and photoresist removal. The image was acquired with a JSM-7000F (JEOL, Japan). The microchip shows precision-diced edges. It has a straight edge and right angles. These features facilitated the alignment of the two windows on the stacking microchips. The lengths of the diced microchips were measured with a high-accuracy micrometer (MDH-25 MB, Mitutoyo, Japan). The designed microchips were square in shape and had dimensions of 6.15 mm × 6.15 mm. Because the saw removed a certain thickness of material from the edges during the dicing, the obtained microchips were smaller than the designed microchips. The average edge length of 10 individual microchips was 6.1102 ± 0.0033 mm. The small deviation of the dimensions demonstrated the high dicing precision. The windows were intact as shown in Fig. 4b. The image was obtained with an Olympus BX51 (Olympus, Japan). The photoresists successfully protected the thin membrane window from being damaged. The buckling profile on the freestanding membrane window was common and probably related to the residual stress (<100 MPa), the window size and the thickness of the SiNx membrane [18,19]. Fig. 4. Open in new tabDownload slide (a) Scanning electron microscopy image of a corner region of a microchip with the SiO2 spacer viewed from the top side surface and (b) optical microscopy image of the freestanding membrane on the top surface of the microchip. Buckling is seen on the membrane. Fig. 4. Open in new tabDownload slide (a) Scanning electron microscopy image of a corner region of a microchip with the SiO2 spacer viewed from the top side surface and (b) optical microscopy image of the freestanding membrane on the top surface of the microchip. Buckling is seen on the membrane. After the photoresist removal, the microchips were rinsed with Milli-Q water and acetone. The oxygen plasma asher was applied to eliminate organic contaminant and render the top surface hydrophilic. Device performance was evaluated with a Pt colloidal suspension (4 wt.% Pt TMA-type, TANAKA Precious Metals, Japan). The Pt had an average size of 2 nm. The suspension was diluted by a factor of 1000. A droplet of the diluted solution was pipetted onto the window and spread on the top surface of the microchip with the spacer. Because the membrane was surrounded by the spacer, the liquid filled the space enclosed by the spacer. The other microchip without the spacer was stacked onto the former microchip with its top surface facing the liquid sample, and their windows were parallel. The liquid was sandwiched between two membrane windows this way. The assembly process is schematically described in Supplementary Fig. S1. The stacking microchips were loaded into the pocket of a specially designed LC holding device as illustrated in Fig. 5a. Fig. 5b is a schematic of the cross section of the sandwiched microchips sealed in the LC holding device. The LC holding device mainly consists of a bottom support and a top lid. The support is covered with the lid. Three O-rings are used to isolate the liquid sample from the outside. The small O-rings surround the bores on the top lid and bottom support. The large O-ring is placed between the lid and support to suppress liquid diffusion from their interface. Four screws are used to connect the lid with the support and to compress the O-rings. Fig. 5. Open in new tabDownload slide (a) Specially designed LC holding device within which an LC is confined, (b) schematic of the cross section of the LC holding device and (c) the LC holding device mounted onto a JEOL single-tilt holder shaft. Fig. 5. Open in new tabDownload slide (a) Specially designed LC holding device within which an LC is confined, (b) schematic of the cross section of the LC holding device and (c) the LC holding device mounted onto a JEOL single-tilt holder shaft. For mitigating the charging and heating effects of the electron beam on the LC, the assembled LC holding device was loaded into the chamber of a plasma etching and coating system (PECS, Model 682, Gatan Inc, USA) and the system was operated in coating mode. The outer surface of the exposed membrane windows would be coated by 1 nm carbon. The LC device was put on the head of a JEOL single-tilt holder (EM-21010 (SCSH), JEOL, Japan) as shown in Fig. 5c. LCTEM observation was conducted with a JEM-2100F (JEOL, Japan) equipped with a Gatan Enfina electron energy-loss spectroscopy (EELS) system. The acceleration voltage of the TEM was 200 kV, and the electron flux fell in the range of 13.2–688.8 e–/(s Å2). The TEM mode images were recorded. The exposure time was 0.3 s. EELS was used to quantify the sample thickness during TEM observation. To record videos, the TEM was set into search mode, where the TEM images were continuously displayed on the computer monitor. The image frames on the screen were directly streamed into video files with a free video recording software (AG desktop recorder, T. Ishii, Japan). The videos had a frame rate of 10 frames/s. Results and discussion Figure 6a–d show the images of the LC viewed from the top and bottom windows after the assembly. Fig. 6a and c are light reflection images. Fringes with rainbow-like colors were seen using the mentioned optical microscope, which has a white light source. In the light transmission images in Fig. 6b and d, the bright regions correspond to the overlapped region of the two windows. A large viewing area of ∼180 µm × 40 µm is available for the electron transmission, though the two windows are not perfectly overlapped. The misalignment along the width direction is much less than that along the length direction. The length edges of the two windows in the overlapped region are close. The mismatch of the two windows along the width direction measured from the top side is ∼7 µm (yellow box in Fig. 6a), while the two edges of the two membranes nearly overlap when viewed from the bottom window (yellow box in Fig. 6b). Fig. 6. Open in new tabDownload slide (a) and (b) Optical microscope images of the top membrane; (c) and (d) optical microscope images of the bottom membrane. (a) and (c) Light reflection images, and (b) and (d) light transmission images. Fig. 6. Open in new tabDownload slide (a) and (b) Optical microscope images of the top membrane; (c) and (d) optical microscope images of the bottom membrane. (a) and (c) Light reflection images, and (b) and (d) light transmission images. The different mismatches along the width on the top and bottom windows are mainly caused by the different window widths. The width of the top window was ∼47 µm, while that of the bottom window was ∼40 µm. The window widths (47 and 40 µm) were smaller than the designed value (50 µm) likely because the wafer used was thicker than 380 µm, and the designed width was calculated assuming that the thickness of all the wafers was 380 µm. However, the 25 purchased wafers have a thickness deviation of ±25 µm, i.e. the thickness of the wafers lies in the range of 380 ± 25 µm. The window size depends on the wafer thickness through the equation W = L − 2 × T × cot54.7°, where W is the window width on the top surface, L is the width of the window pattern on the bottom surface, T is the wafer thickness and 54.7° is the dihedral angle between the <100> and <111> planes of the Si wafer. The window width is small when a thick wafer is used. The different window widths in the same wafer may be caused by the wafer thickness variation or the wet etching process. The total thickness variation of an individual Si wafer is ≤5 µm. This means that the thickness deviation for one wafer is ≤5 µm. Because the two chips that formed an LC were neighbors on the Si wafer, the distance between two neighboring windows was ∼6 mm on the 3-inch wafer. The thickness variation over this 6-mm distance should be <5 µm because the wafers were polished on both sides. From the equation, the window width difference caused by the thickness variation of 5 µm was <7 µm. Meanwhile, we observed that the membrane window close to the edge of the wafer generally appeared first, and that in the central region emerged at last during the wet etching. The etching was carried out in a KOH bath. The KOH etching rate is slow when the etching temperature is low and the concentration of the etching solution is low. The etching lasted ∼8 h, during which there was probably a decreasing gradient of the temperature or etching species from the edge and central part of the Si wafer. This led to the different window widths in the same wafer. Two aspects may be responsible for the apparent misalignment along the length direction. The first is that the windows were not strictly on the center of the two microchips because of the dimensional deviations during the patterning and dicing. During stacking of the two microchips, one of the microchips was flipped upside down around one of its edges parallel to the window’s width edge. Supplementary Fig. S2 shows the stacking process. Because the two microchips were cut from the same wafer, the windows were at almost identical positions on the two microchips. This led to the window along the width more likely matching than that along the length with this stacking method. The second possible reason is the gap between the edges of the stacking microchips and the walls of the pocket. The pocket had dimensions of 6.15 × 6.15 mm2, while the dimensions of the individual microchips were, as described above, ∼6.11 × 6.11 mm2. When the screws were tightened to compress the microchips, the two microchips would likely have slightly shifted on the surface of the sandwiched liquid sample. The movement could cause window misalignment not only along the length direction but also along the width direction. The light fringes in Fig. 6a and c suggest that the membrane windows bulged outward as the two microchips were pressed together [7]. The deformation may be due to the higher internal pressure of the liquid than that of the atmosphere. As the membrane curvature gradually increased from the edge of the membrane, the distance between the two membranes increased from the edge to the center of the membrane. The interference between incident and reflected lights generated the fringes. The bulging magnitude of the membranes was determined with an optical microscope (VANOX AHMT3, Olympus, Japan) that provided a single light wavelength of ∼540 nm (green light). The maximum bulging was in the central region of the membranes and was estimated to be >1430 nm [7]. The liquid thickness near the closely overlapped edge was calculated to be 125.6 nm (see the supplementary data online), where nanoscale resolution could be achieved. The Pt nanoparticles in the liquid could be clearly observed near the edge (Fig. 7a). In the 0.004 wt.% Pt suspension, the average distance between two nanoparticles was estimated to be 4.5 ± 1.0 nm. We assume that stably dispersed individual nanoparticles occupied a cubic volume in the solution. The calculated distance between the individual nanoparticles in the diluted solution was ∼5.6 µm. The distance in the LC was three orders of magnitude shorter than that in the suspension. Because the Pt nanoparticles were negatively charged, the SiNx membranes windows were considered positively charged upon the electron illumination [20]. One possible explanation for the shortened distance is that the nanoparticles in the bulk liquid were attracted and attached to the window owing to the electrostatic attractive force between the nanoparticles and the membrane [21]. Fig. 7. Open in new tabDownload slide Nanoparticle distribution in the field of view (a) at the beginning and (b) after 197 s of the in situ LCTEM observation. Fig. 7. Open in new tabDownload slide Nanoparticle distribution in the field of view (a) at the beginning and (b) after 197 s of the in situ LCTEM observation. Video S1 shows the evolution of the nanoparticles in the field of view. Various motions were observed such as rotation, jumping, translation, collision–separation and coalescence. The translational motion was transient rather than continual. The displacement of the nanoparticles at every step was on the order of nanometers, significantly shorter than the micrometer-scale step of free nanoparticles in Brownian motion [22]. After 197 s of electron beam illumination, the individual nanoparticles gradually aggregated into short chains as shown in Fig. 7b. The mechanism of the aggregate formation is still debated [20,21,23]. The Pt nanoparticles became colloidal nanoparticles as they were dispersed in the aqueous solution. One possible explanation is the interactions between the 200 keV electrons and irradiated water molecules. The interaction could yield hydrated electrons eh−, H3O+, hydrogen radical, hydroxyl radical and H2 [24,25]. The charged radiolytic products increased the ion strength and decreased pH of the medium. These two aspects reduced the stability of the colloidal Pt nanoparticles and induced the aggregation. Concluding remarks We presented an efficient and wafer-scale microchip production approach. The yield of the microchips reached 100%. The new feature of the production was forming the positioning reference marks on the SiNx-coated Si wafer. The positioning reference marks and membrane windows were simultaneously formed on the top surface of the wafer with the same microfabrication procedures. The positioning reference marks were through holes, which not only guided the creation of a spacer pattern on the top surface but also effectively navigated the dicing machine to cut the Si wafer precisely. The precise dimensions of the microchips eased the alignment of the windows during the microchip stacking. The windows had a parallel configuration, which provided a large overlapped view area of 180 µm × 40 µm after the microchips were enclosed in the designed holding device. Though the two windows were not perfectly overlapped, the misalignment along the width direction was less significant and facilitated the close superposition of the windows along the length edge (180 µm). The thickness of the liquid sample close to the edge was measured to be 125.6 nm, where the dynamic motions of Pt nanoparticles with an average size of 2 nm were clearly observed. The result demonstrated that the LC fabricated in this work functioned well with the TEM. Acknowledgements The authors thank Eichiro Watanabe, Hirotaka Osato and Daiju Tsuya of the NIMS nanofabrication platform for their valuable advice and help during the microchip fabrication; Akira Hasegawa and Ichie Koda of the NIMS TEM station for their assistance during the TEM characterization; Ayako Hashimoto for providing the Pt nanoparticle sample and high-vacuum station for the leak test of the liquid cell; and Mark Kurban from Edanz Group (https://en-author-services.edanzgroup.com/ac) for editing a draft of this manuscript. Author contributions X.L. designed and performed the experiments, M.T. planned and supervised the work and K.M. aided in interpreting the results and worked on the manuscript. All authors discussed the results and commented on the manuscript. Conflict of interest The authors declare no conflict of interest concerning the materials and methods used in this study or the findings specified in this paper. Supplementary data Supplementary data are available at Microscopy online. References 1. De Jonge N and Ross F ( 2011 ) Electron microscopy of specimens in liquid . Nat. Nanotechnol. 6 : 695 – 704 . doi: 10.1038/nnano.2011.161 Google Scholar Crossref Search ADS PubMed WorldCat 2. Ross F ( 2015 ) Opportunities and challenges in liquid cell electron microscopy . Science 350 : 9886. doi: 10.1126/science.aaa9886 Google Scholar OpenURL Placeholder Text WorldCat Crossref 3. De Jonge N , Houben L, Dunin-Borkowski R, and Ross F ( 2019 ) Resolution and aberration correction in liquid cell transmission electron microscopy . Nat. Rev. Mater. 4 : 61 – 78 . doi: 10.1038/s41578-018-0071-2 Google Scholar Crossref Search ADS WorldCat 4. Van Omme J , Wu H, Sun H, Beker A, Lemang M, Spruit R, Maddala S, Rokowski A, Friedrich H, Patterson J, and Garza H ( 2020 ) Liquid phase transmission electron microscopy with flow and temperature control . J. Mater. Chem. C 8 : 10781 – 10790 . doi: 10.1039/D0TC01103G Google Scholar Crossref Search ADS WorldCat 5. Mehdi B , Gu M, Parent L, Xu W, Nasybulin E, Chen X, Unocic R, Xu P, Welch D, Abellan P, Zhang J, Liu J, Wang C, Arslan I, Evans J, and Browning N ( 2014 ) In-situ electrochemical transmission electron microscopy for battery research . Microsc. Microanal. 20 : 484 – 492 . doi: 10.1017/S1431927614000488 Google Scholar Crossref Search ADS PubMed WorldCat 6. Unocic R , Sacci R, Brown G, Veith G M, Dudney N, More K, Walden F, Gardiner D, Damiano J, and Nackashi D ( 2014 ) Quantitative electrochemical measurements using in situ ec-S/TEM devices . Microsc. Microanal. 20 : 452 – 461 . doi: 10.1017/S1431927614000166 Google Scholar Crossref Search ADS PubMed WorldCat 7. Grogan J and Bau H ( 2010 ) The nanoaquarium: a platform for in situ transmission electron microscopy in liquid media . J. Microelectromech. Syst. 19 : 885 – 894 . doi: 10.1109/JMEMS.2010.2051321 Google Scholar Crossref Search ADS WorldCat 8. Holtz M , Yu Y, Gao J, Abruna H, and Muller D ( 2013 ) In situ electron energy-loss spectroscopy in liquids . Microsc. Microanal. 4 : 1027 – 1035 . doi: 10.1017/S1431927613001505 Google Scholar Crossref Search ADS WorldCat 9. Jensen E Mølhave K ( 2016 ) Encapsulated liquid cells for transmission electron microscopy. In: Ross F (ed.), Liquid Cell Electron Microscopy , pp 35 – 55 ( Cambridge University Press , Cambridge ). Google Scholar Crossref Search ADS Google Preview WorldCat COPAC 10. Huang T , Liu S, Chuang Y, Hsieh H, Tsai C, Huang Y, Mirsaidov U, Matsudaira P, Tseng F, Chang C, and Chen F ( 2012 ) Self-aligned wet-cell for hydrated microbiology observation in TEM . Lab Chip 12 : 340 – 347 . doi: 10.1039/C1LC20647H Google Scholar Crossref Search ADS PubMed WorldCat 11. Leenheer A , Sullivan J, Shaw M, and Harris C ( 2015 ) A sealed liquid cell for in situ transmission electron microscopy of controlled electrochemical processes . J. Microelectromech. Syst. 24 : 1061 – 1068 . doi: 10.1109/JMEMS.2014.2380771 Google Scholar Crossref Search ADS WorldCat 12. Ring E and De Jonge N ( 2010 ) Microfluidic system for transmission electron microscopy . Microsc. Microanal. 16 : 622 – 629 . doi: 10.1017/S1431927610093669 Google Scholar Crossref Search ADS PubMed WorldCat 13. Kim B , Heo J, Lee W, and Park J ( 2017 ) Liquid-cell transmission electron microscopy for tracking self-assembly of nanoparticles . JoVE 128 : e56335. Google Scholar OpenURL Placeholder Text WorldCat 14. Ring E , Peckys D, Dukes M, Baudoin J, and De Jonge N ( 2011 ) Silicon nitride windows for electron microscopy of whole cells . J. Microsc. 243 : 273 – 283 . doi: 10.1111/j.1365-2818.2011.03501.x Google Scholar Crossref Search ADS PubMed WorldCat 15. Grant A , Hu Q, and Kasemo B ( 2004 ) Transmission electron microscopy ‘windows’ for nanofabricated structures . Nanotechnology 15 : 1175 – 1181 . doi: 10.1088/0957-4484/15/9/012 Google Scholar Crossref Search ADS WorldCat 16. Ramachandra R , Demers H, and De Jonge N ( 2011 ) Atomic-resolution scanning transmission electron microscopy through 50-nm-thick silicon nitride membranes . Appl. Phys. Lett. 98 : 2009 – 2012 . doi: 10.1063/1.3561758 Google Scholar Crossref Search ADS WorldCat 17. Singh S , Pal P, Pandey A, Xing Y, and Sato K ( 2016 ) Determination of precise crystallographic directions for mask alignment in wet bulk micromachining for MEMS . Micro Nano Syst. Lett. 4 : 65 – 67 . doi: 10.1186/s40486-016-0027-5 Google Scholar Crossref Search ADS WorldCat 18. Ziebart V , Paul O, and Baltes H ( 1999 ) Strongly buckled square micromachined membranes . J. Microelectromech. Syst. 8 : 8423 – 8432 . doi: 10.1109/84.809057 Google Scholar Crossref Search ADS WorldCat 19. Kerman K , Tallinen T, Ramanathan S, and Mahadevan L ( 2013 ) Elastic configurations of self-supported oxide membranes for fuel cells . J. Power Sour. 222 : 359 – 366 . doi: 10.1016/j.jpowsour.2012.08.092 Google Scholar Crossref Search ADS WorldCat 20. Woehl T and Prozorov T ( 2015 ) The mechanisms for nanoparticle surface diffusion and chain self-assembly determined from real-time nanoscale kinetics in liquid . J. Phys. Chem. C 119 : 21261 – 21269 . doi: 10.1021/acs.jpcc.5b07164 Google Scholar Crossref Search ADS WorldCat 21. Liu Y , Lin X, Sun Y, and Rajh T ( 2013 ) In situ visualization of self-assembly of charged gold nanoparticles . J. Am. Chem. Soc. 135 : 3764 – 3767 . doi: 10.1021/ja312620e Google Scholar Crossref Search ADS PubMed WorldCat 22. Ring E and De Jonge N ( 2012 ) Video-frequency scanning transmission electron microscopy of moving gold nanoparticles in liquid . Micron 43 : 1078 – 1084 . doi: 10.1016/j.micron.2012.01.010 Google Scholar Crossref Search ADS PubMed WorldCat 23. Tian X , Zheng H, and Mirsaidov U ( 2017 ) Aggregation dynamics of nanoparticles at solid-liquid interfaces . Nanoscale 9 : 10044 – 10050 . doi: 10.1039/C7NR01985H Google Scholar Crossref Search ADS PubMed WorldCat 24. Schneider N , Norton M, Mendel B, Grogan J, Ross F, and Bau H ( 2014 ) Electron-water interactions and implications for liquid cell electron microscopy . J. Phys. Chem. C 118 : 22373 – 22382 . doi: 10.1021/jp507400n Google Scholar Crossref Search ADS WorldCat 25. Abellan P , Woehl T, Parent L, Browning N, Evans J, and Arslan I ( 2014 ) Factors influencing quantitative liquid (scanning) transmission electron microscopy . Chem. Commun. 50 : 4873 – 4880 . doi: 10.1039/C3CC48479C Google Scholar Crossref Search ADS WorldCat Published by Oxford University Press on behalf of The Japanese Society of Microscopy 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US. This work is written by (a) US Government employee(s) and is in the public domain in the US. Published by Oxford University Press on behalf of The Japanese Society of Microscopy 2021. This work is written by (a) US Government employee(s) and is in the public domain in the US.
TI - Fabrication of a liquid cell for in situ transmission electron microscopy
JF - Journal of Electron Microscopy
DO - 10.1093/jmicro/dfaa076
DA - 2021-08-09
UR - https://www.deepdyve.com/lp/oxford-university-press/fabrication-of-a-liquid-cell-for-in-situ-transmission-electron-70CpNulFZJ
SP - 327
EP - 332
VL - 70
IS - 4
DP - DeepDyve
ER -