Journal articles: 'High-density silicon probe recording'

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Egert, Daniel, Jeffrey R. Pettibone, Stefan Lemke, Paras R. Patel, Ciara M. Caldwell, Dawen Cai, Karunesh Ganguly, Cynthia A. Chestek, and Joshua D. Berke. "Cellular-scale silicon probes for high-density, precisely localized neurophysiology." Journal of Neurophysiology 124, no. 6 (December 1, 2020): 1578–87. http://dx.doi.org/10.1152/jn.00352.2020.

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Devices with many electrodes penetrating into the brain are an important tool for investigating neural information processing, but they are typically large compared with neurons. This results in substantial damage and makes it harder to reconstruct recording locations within brain circuits. This paper presents high-channel-count silicon probes with much smaller features and a method for slicing through probe, brain, and skull all together. This allows probe tips to be directly observed relative to immunohistochemical markers.

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Csicsvari, Jozsef, Darrell A. Henze, Brian Jamieson, Kenneth D. Harris, Anton Sirota, Péter Barthó, Kensall D. Wise, and György Buzsáki. "Massively Parallel Recording of Unit and Local Field Potentials With Silicon-Based Electrodes." Journal of Neurophysiology 90, no. 2 (August 2003): 1314–23. http://dx.doi.org/10.1152/jn.00116.2003.

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Parallel recording of neuronal activity in the behaving animal is a prerequisite for our understanding of neuronal representation and storage of information. Here we describe the development of micro-machined silicon microelectrode arrays for unit and local field recordings. The two-dimensional probes with 96 or 64 recording sites provided high-density recording of unit and field activity with minimal tissue displacement or damage. The on-chip active circuit eliminated movement and other artifacts and greatly reduced the weight of the headgear. The precise geometry of the recording tips allowed for the estimation of the spatial location of the recorded neurons and for high-resolution estimation of extracellular current source density. Action potentials could be simultaneously recorded from the soma and dendrites of the same neurons. Silicon technology is a promising approach for high-density, high-resolution sampling of neuronal activity in both basic research and prosthetic devices.

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Scholvin, Jörg, Anthony Zorzos, Justin Kinney, Jacob Bernstein, Caroline Moore-Kochlacs, Nancy Kopell, Clifton Fonstad, and Edward Boyden. "Scalable, Modular Three-Dimensional Silicon Microelectrode Assembly via Electroless Plating." Micromachines 9, no. 9 (August 30, 2018): 436. http://dx.doi.org/10.3390/mi9090436.

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We devised a scalable, modular strategy for microfabricated 3-D neural probe synthesis. We constructed a 3-D probe out of individual 2-D components (arrays of shanks bearing close-packed electrodes) using mechanical self-locking and self-aligning techniques, followed by electroless nickel plating to establish electrical contact between the individual parts. We detail the fabrication and assembly process and demonstrate different 3-D probe designs bearing thousands of electrode sites. We find typical self-alignment accuracy between shanks of <0.2° and demonstrate orthogonal electrical connections of 40 µm pitch, with thousands of connections formed electrochemically in parallel. The fabrication methods introduced allow the design of scalable, modular electrodes for high-density 3-D neural recording. The combination of scalable 3-D design and close-packed recording sites may support a variety of large-scale neural recording strategies for the mammalian brain.

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Wei, Wen Jing, Yi Lin Song, Wen Tao Shi, Chun Xiu Liu, Ting Jun Jiang, and Xin Xia Cai. "A Novel Microelectrode Array Probe Integrated with Electrophysiology Reference Electrode for Neural Recording." Key Engineering Materials 562-565 (July 2013): 67–73. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.67.

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Nowadays, the study of brain function is advanced by implantable microelectrode arrays for they can simultaneously record signals from different groups of neurons regarding complex neural processes. This article presents the fabrication, characterization and use in vivo neural recording of an implantable microelectrode array probe which integrated with electrophysiology reference electrode. The probe was implemented on Silicon-On-Insulator (SOI) wafer using Micro-Electro-Mechanical-Systems (MEMS) methods, so the recording-site configurations and high-density electrode placement could be precisely defined. The 16 recording sites and the reference electrode were made of platinum. Double layers of platinum electrodes were used so that the width of the reference electrode was as small as 6 μm. The average impedance of the microelectrodes was 0.13 MΩ at 1 kHz. The probe has been employed to record the neural signals of rat, and the results showed that the signal-to-noise ratio (SNR) of the novel probe was as high as 10 and the ordinary probe was 3. Among the 16 recording sites, there are 9 effective sites having recorded useful signals for the probe with reference electrode and 6 for the ordinary probe.

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Fiáth, Richárd, Patrícia Beregszászi, Domonkos Horváth, Lucia Wittner, Arno A. A. Aarts, Patrick Ruther, Hercules P. Neves, Hajnalka Bokor, László Acsády, and István Ulbert. "Large-scale recording of thalamocortical circuits: in vivo electrophysiology with the two-dimensional electronic depth control silicon probe." Journal of Neurophysiology 116, no. 5 (November 1, 2016): 2312–30. http://dx.doi.org/10.1152/jn.00318.2016.

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Recording simultaneous activity of a large number of neurons in distributed neuronal networks is crucial to understand higher order brain functions. We demonstrate the in vivo performance of a recently developed electrophysiological recording system comprising a two-dimensional, multi-shank, high-density silicon probe with integrated complementary metal-oxide semiconductor electronics. The system implements the concept of electronic depth control (EDC), which enables the electronic selection of a limited number of recording sites on each of the probe shafts. This innovative feature of the system permits simultaneous recording of local field potentials (LFP) and single- and multiple-unit activity (SUA and MUA, respectively) from multiple brain sites with high quality and without the actual physical movement of the probe. To evaluate the in vivo recording capabilities of the EDC probe, we recorded LFP, MUA, and SUA in acute experiments from cortical and thalamic brain areas of anesthetized rats and mice. The advantages of large-scale recording with the EDC probe are illustrated by investigating the spatiotemporal dynamics of pharmacologically induced thalamocortical slow-wave activity in rats and by the two-dimensional tonotopic mapping of the auditory thalamus. In mice, spatial distribution of thalamic responses to optogenetic stimulation of the neocortex was examined. Utilizing the benefits of the EDC system may result in a higher yield of useful data from a single experiment compared with traditional passive multielectrode arrays, and thus in the reduction of animals needed for a research study.

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Jun, James J., Nicholas A. Steinmetz, Joshua H. Siegle, Daniel J. Denman, Marius Bauza, Brian Barbarits, Albert K. Lee, et al. "Fully integrated silicon probes for high-density recording of neural activity." Nature 551, no. 7679 (November 9, 2017): 232–36. http://dx.doi.org/10.1038/nature24636.

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Novais, Ashley, Carlos Calaza, José Fernandes, Helder Fonseca, Patricia Monteiro, João Gaspar, and Luis Jacinto. "Hybrid Multisite Silicon Neural Probe with Integrated Flexible Connector for Interchangeable Packaging." Sensors 21, no. 8 (April 8, 2021): 2605. http://dx.doi.org/10.3390/s21082605.

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Multisite neural probes are a fundamental tool to study brain function. Hybrid silicon/polymer neural probes combine rigid silicon and flexible polymer parts into one single device and allow, for example, the precise integration of complex probe geometries, such as multishank designs, with flexible biocompatible cabling. Despite these advantages and benefiting from highly reproducible fabrication methods on both silicon and polymer substrates, they have not been widely available. This paper presents the development, fabrication, characterization, and in vivo electrophysiological assessment of a hybrid multisite multishank silicon probe with a monolithically integrated polyimide flexible interconnect cable. The fabrication process was optimized at wafer level, and several neural probes with 64 gold electrode sites equally distributed along 8 shanks with an integrated 8 µm thick highly flexible polyimide interconnect cable were produced. The monolithic integration of the polyimide cable in the same fabrication process removed the necessity of the postfabrication bonding of the cable to the probe. This is the highest electrode site density and thinnest flexible cable ever reported for a hybrid silicon/polymer probe. Additionally, to avoid the time-consuming bonding of the probe to definitive packaging, the flexible cable was designed to terminate in a connector pad that can mate with commercial zero-insertion force (ZIF) connectors for electronics interfacing. This allows great experimental flexibility because interchangeable packaging can be used according to experimental demands. High-density distributed in vivo electrophysiological recordings were obtained from the hybrid neural probes with low intrinsic noise and high signal-to-noise ratio (SNR).

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Fu, Tian-Ming, Guosong Hong, Robert D. Viveros, Tao Zhou, and Charles M. Lieber. "Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology." Proceedings of the National Academy of Sciences 114, no. 47 (November 6, 2017): E10046—E10055. http://dx.doi.org/10.1073/pnas.1717695114.

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Implantable electrical probes have led to advances in neuroscience, brain−machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases.

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Yatsui, Takashi, Motonobu Kourogi, Kazuo Tsutsui, Motoichi Ohtsu, and Jun-ichi Takahashi. "High-density–speed optical near-field recording–reading with a pyramidal silicon probe on a contact slider." Optics Letters 25, no. 17 (September 1, 2000): 1279. http://dx.doi.org/10.1364/ol.25.001279.

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Berényi, Antal, Zoltán Somogyvári, Anett J. Nagy, Lisa Roux, John D. Long, Shigeyoshi Fujisawa, Eran Stark, Anthony Leonardo, Timothy D. Harris, and György Buzsáki. "Large-scale, high-density (up to 512 channels) recording of local circuits in behaving animals." Journal of Neurophysiology 111, no. 5 (March 1, 2014): 1132–49. http://dx.doi.org/10.1152/jn.00785.2013.

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Monitoring representative fractions of neurons from multiple brain circuits in behaving animals is necessary for understanding neuronal computation. Here, we describe a system that allows high-channel-count recordings from a small volume of neuronal tissue using a lightweight signal multiplexing headstage that permits free behavior of small rodents. The system integrates multishank, high-density recording silicon probes, ultraflexible interconnects, and a miniaturized microdrive. These improvements allowed for simultaneous recordings of local field potentials and unit activity from hundreds of sites without confining free movements of the animal. The advantages of large-scale recordings are illustrated by determining the electroanatomic boundaries of layers and regions in the hippocampus and neocortex and constructing a circuit diagram of functional connections among neurons in real anatomic space. These methods will allow the investigation of circuit operations and behavior-dependent interregional interactions for testing hypotheses of neural networks and brain function.

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Goncalves, S., José Palha, Helena Fernandes, Márcio Souto, Sara Pimenta, Tao Dong, Zhaochu Yang, João Ribeiro, and José Correia. "LED Optrode with Integrated Temperature Sensing for Optogenetics." Micromachines 9, no. 9 (September 17, 2018): 473. http://dx.doi.org/10.3390/mi9090473.

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In optogenetic studies, the brain is exposed to high-power light sources and inadequate power density or exposure time can cause cell damage from overheating (typically temperature increasing of 2 ∘ C). In order to overcome overheating issues in optogenetics, this paper presents a neural tool capable of assessing tissue temperature over time, combined with the capability of electrical recording and optical stimulation. A silicon-based 8 mm long probe was manufactured to reach deep neural structures. The final proof-of-concept device comprises a double-sided function: on one side, an optrode with LED-based stimulation and platinum (Pt) recording points; and, on the opposite side, a Pt-based thin-film thermoresistance (RTD) for temperature assessing in the photostimulation site surroundings. Pt thin-films for tissue interface were chosen due to its biocompatibility and thermal linearity. A single-shaft probe is demonstrated for integration in a 3D probe array. A 3D probe array will reduce the distance between the thermal sensor and the heating source. Results show good recording and optical features, with average impedance magnitude of 371 k Ω , at 1 kHz, and optical power of 1.2 mW·mm − 2 (at 470 nm), respectively. The manufactured RTD showed resolution of 0.2 ∘ C at 37 ∘ C (normal body temperature). Overall, the results show a device capable of meeting the requirements of a neural interface for recording/stimulating of neural activity and monitoring temperature profile of the photostimulation site surroundings, which suggests a promising tool for neuroscience research filed.

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Guo, Bangbang, Ye Fan, Minghao Wang, Yuhua Cheng, Bowen Ji, Ying Chen, and Gaofeng Wang. "Flexible Neural Probes with Electrochemical Modified Microelectrodes for Artifact-Free Optogenetic Applications." International Journal of Molecular Sciences 22, no. 21 (October 26, 2021): 11528. http://dx.doi.org/10.3390/ijms222111528.

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With the rapid increase in the use of optogenetics to investigate nervous systems, there is high demand for neural interfaces that can simultaneously perform optical stimulation and electrophysiological recording. However, high-magnitude stimulation artifacts have prevented experiments from being conducted at a desirably high temporal resolution. Here, a flexible polyimide-based neural probe with polyethylene glycol (PEG) packaged optical fiber and Pt-Black/PEDOT-GO (graphene oxide doped poly(3,4-ethylene-dioxythiophene)) modified microelectrodes was developed to reduce the stimulation artifacts that are induced by photoelectrochemical (PEC) and photovoltaic (PV) effects. The advantages of this design include quick and accurate implantation and high-resolution recording capacities. Firstly, electrochemical performance of the modified microelectrodes is significantly improved due to the large specific surface area of the GO layer. Secondly, good mechanical and electrochemical stability of the modified microelectrodes is obtained by using Pt-Black as bonding layer. Lastly, bench noise recordings revealed that PEC noise amplitude of the modified neural probes could be reduced to less than 50 µV and no PV noise was detected when compared to silicon-based neural probes. The results indicate that this device is a promising optogenetic tool for studying local neural circuits.

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Klein, Liane, Frederick Pothof, Bogdan C. Raducanu, Johanna Klon-Lipok, Katharine A. Shapcott, Silke Musa, Alexandru Andrei, et al. "High-density electrophysiological recordings in macaque using a chronically implanted 128-channel passive silicon probe." Journal of Neural Engineering 17, no. 2 (April 29, 2020): 026036. http://dx.doi.org/10.1088/1741-2552/ab8436.

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Stark, Eran, Tibor Koos, and György Buzsáki. "Diode probes for spatiotemporal optical control of multiple neurons in freely moving animals." Journal of Neurophysiology 108, no. 1 (July 1, 2012): 349–63. http://dx.doi.org/10.1152/jn.00153.2012.

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Neuronal control with high temporal precision is possible with optogenetics, yet currently available methods do not enable to control independently multiple locations in the brains of freely moving animals. Here, we describe a diode-probe system that allows real-time and location-specific control of neuronal activity at multiple sites. Manipulation of neuronal activity in arbitrary spatiotemporal patterns is achieved by means of an optoelectronic array, manufactured by attaching multiple diode-fiber assemblies to high-density silicon probes or wire tetrodes and implanted into the brains of animals that are expressing light-responsive opsins. Each diode can be controlled separately, allowing localized light stimulation of neuronal activators and silencers in any temporal configuration and concurrent recording of the stimulated neurons. Because the only connections to the animals are via a highly flexible wire cable, unimpeded behavior is allowed for circuit monitoring and multisite perturbations in the intact brain. The capacity of the system to generate unique neural activity patterns facilitates multisite manipulation of neural circuits in a closed-loop manner and opens the door to addressing novel questions.

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Perpetuini, David, Antonio Maria Chiarelli, Lidia Maddiona, Sergio Rinella, Francesco Bianco, Valentina Bucciarelli, Sabina Gallina, et al. "Multi-Site Photoplethysmographic and Electrocardiographic System for Arterial Stiffness and Cardiovascular Status Assessment." Sensors 19, no. 24 (December 17, 2019): 5570. http://dx.doi.org/10.3390/s19245570.

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The development and validation of a system for multi-site photoplethysmography (PPG) and electrocardiography (ECG) is presented. The system could acquire signals from 8 PPG probes and 10 ECG leads. Each PPG probe was constituted of a light-emitting diode (LED) source at a wavelength of 940 nm and a silicon photomultiplier (SiPM) detector, located in a back-reflection recording configuration. In order to ensure proper optode-to-skin coupling, the probe was equipped with insufflating cuffs. The high number of PPG probes allowed us to simultaneously acquire signals from multiple body locations. The ECG provided a reference for single-pulse PPG evaluation and averaging, allowing the extraction of indices of cardiovascular status with a high signal-to-noise ratio. Firstly, the system was characterized on optical phantoms. Furthermore, in vivo validation was performed by estimating the brachial-ankle pulse wave velocity (baPWV), a metric associated with cardiovascular status. The validation was performed on healthy volunteers to assess the baPWV intra- and extra-operator repeatability and its association with age. Finally, the baPWV, evaluated via the developed instrumentation, was compared to that estimated with a commercial system used in clinical practice (Enverdis Vascular Explorer). The validation demonstrated the system’s reliability and its effectiveness in assessing the cardiovascular status in arterial ageing.

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Barthó, Peter, Hajime Hirase, Lenaïc Monconduit, Michael Zugaro, Kenneth D. Harris, and György Buzsáki. "Characterization of Neocortical Principal Cells and Interneurons by Network Interactions and Extracellular Features." Journal of Neurophysiology 92, no. 1 (July 2004): 600–608. http://dx.doi.org/10.1152/jn.01170.2003.

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Most neuronal interactions in the cortex occur within local circuits. Because principal cells and GABAergic interneurons contribute differently to cortical operations, their experimental identification and separation is of utmost important. We used 64-site two-dimensional silicon probes for high-density recording of local neurons in layer 5 of the somatosensory and prefrontal cortices of the rat. Multiple-site monitoring of units allowed for the determination of their two-dimensional spatial position in the brain. Of the ∼60,000 cell pairs recorded, 0.2% showed robust short-term interactions. Units with significant, short-latency (<3 ms) peaks following their action potentials in their cross-correlograms were characterized as putative excitatory (pyramidal) cells. Units with significant suppression of spiking of their partners were regarded as putative GABAergic interneurons. A portion of the putative interneurons was reciprocally connected with pyramidal cells. Neurons physiologically identified as inhibitory and excitatory cells were used as templates for classification of all recorded neurons. Of the several parameters tested, the duration of the unfiltered (1 Hz to 5 kHz) spike provided the most reliable clustering of the population. High-density parallel recordings of neuronal activity, determination of their physical location and their classification into pyramidal and interneuron classes provide the necessary tools for local circuit analysis.

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Hashemi Noshahr, Fereidoon, Morteza Nabavi, and Mohamad Sawan. "Multi-Channel Neural Recording Implants: A Review." Sensors 20, no. 3 (February 7, 2020): 904. http://dx.doi.org/10.3390/s20030904.

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The recently growing progress in neuroscience research and relevant achievements, as well as advancements in the fabrication process, have increased the demand for neural interfacing systems. Brain–machine interfaces (BMIs) have been revealed to be a promising method for the diagnosis and treatment of neurological disorders and the restoration of sensory and motor function. Neural recording implants, as a part of BMI, are capable of capturing brain signals, and amplifying, digitizing, and transferring them outside of the body with a transmitter. The main challenges of designing such implants are minimizing power consumption and the silicon area. In this paper, multi-channel neural recording implants are surveyed. After presenting various neural-signal features, we investigate main available neural recording circuit and system architectures. The fundamental blocks of available architectures, such as neural amplifiers, analog to digital converters (ADCs) and compression blocks, are explored. We cover the various topologies of neural amplifiers, provide a comparison, and probe their design challenges. To achieve a relatively high SNR at the output of the neural amplifier, noise reduction techniques are discussed. Also, to transfer neural signals outside of the body, they are digitized using data converters, then in most cases, the data compression is applied to mitigate power consumption. We present the various dedicated ADC structures, as well as an overview of main data compression methods.

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Luo, Kuan, and Xinyu Jiang. "Detection of Glucose in Human Serum Based on Silicon Dot Probe." Current Analytical Chemistry 16, no. 6 (August 13, 2020): 744–52. http://dx.doi.org/10.2174/1573411015666190702152331.

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Background: Diabetes Mellitus (DM) is a major public metabolic disease that influences 366 million people in the world in 2011, and this number is predicted to rise to 552 million in 2030. DM is clinically diagnosed by a fasting blood glucose that is equal or greater than 7 mM. Therefore, the development of effective glucose biosensor has attracted extensive attention worldwide. Fluorescence- based strategies have sparked tremendous interest due to their rapid response, facile operation, and excellent sensitivity. Many fluorescent compounds have been employed for precise analysis of glucose, including quantum dots, noble metal nanoclusters, up-converting nanoparticles, organic dyes, and composite fluorescent microspheres. Silicon dot as promising quantum dots materials have received extensive attention, owing to their distinct advantages such as biocompatibility, low toxicity and high photostability. Methods: MnO2 nanosheets on the Si nanoparticles (NPs) surface serve as a quencher. Si NPs fluorescence can make a recovery by the addition of H2O2, which can reduce MnO2 to Mn2+, and the glucose can thus be monitored based on the enzymatic conversion of glucose by glucose oxidase to generate H2O2. Therefore, the glucose concentration can be derived by recording the fluorescence recovery spectra of the Si NPs. Results: This probe enabled selective detection of glucose with a linear range of 1-100 μg/mL and a limit of detection of 0.98 μg/mL. Compared with the commercial glucometer, this method showed favorable results and convincing reliability. Conclusion: We have developed a novel method based on MnO2 -nanosheet-modified Si NPs for rapid monitoring of blood glucose levels. By combining the highly sensitive H2O2/MnO2 reaction with the excellent photostability of Si NPs, a highly sensitive, selective, and cost-efficient sensing approach for glucose detection has been designed and applied to monitor glucose levels in human serum with satisfactory results.

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Ashouri Vajari, Danesh, Maria Vomero, Johannes Erhardt, Ali Sadr, Juan Ordonez, Volker Coenen, and Thomas Stieglitz. "Integrity Assessment of a Hybrid DBS Probe that Enables Neurotransmitter Detection Simultaneously to Electrical Stimulation and Recording." Micromachines 9, no. 10 (October 10, 2018): 510. http://dx.doi.org/10.3390/mi9100510.

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Deep brain stimulation (DBS) is a successful medical therapy for many treatment resistant neuropsychiatric disorders such as movement disorders; e.g., Parkinson’s disease, Tremor, and dystonia. Moreover, DBS is becoming more and more appealing for a rapidly growing number of patients with other neuropsychiatric diseases such as depression and obsessive compulsive disorder. In spite of the promising outcomes, the current clinical hardware used in DBS does not match the technological standards of other medical applications and as a result could possibly lead to side effects such as high energy consumption and others. By implementing more advanced DBS devices, in fact, many of these limitations could be overcome. For example, a higher channels count and smaller electrode sites could allow more focal and tailored stimulation. In addition, new materials, like carbon for example, could be incorporated into the probes to enable adaptive stimulation protocols by biosensing neurotransmitters in the brain. Updating the current clinical DBS technology adequately requires combining the most recent technological advances in the field of neural engineering. Here, a novel hybrid multimodal DBS probe with glassy carbon microelectrodes on a polyimide thin-film device assembled on a silicon rubber tubing is introduced. The glassy carbon interface enables neurotransmitter detection using fast scan cyclic voltammetry and electrophysiological recordings while simultaneously performing electrical stimulation. Additionally, the presented DBS technology shows no imaging artefacts in magnetic resonance imaging. Thus, we present a promising new tool that might lead to a better fundamental understanding of the underlying mechanism of DBS while simultaneously paving our way towards better treatments.

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Petford-Long, Amanda K., A. Cerezo, and M. G. Hetherington. "Fabrication and characterization - by High Resolution Electron Microscopy and atom probe microanalysis - of Co-based metallic multilayer films." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 772–73. http://dx.doi.org/10.1017/s042482010017699x.

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The fabrication of multilayer films (MLF) with layer thicknesses down to one monolayer has led to the development of materials with unique properties not found in bulk materials. The properties of interest depend critically on the structure and composition of the films, with the interfacial regions between the layers being of particular importance. There are a number of magnetic MLF systems based on Co, several of which have potential applications as perpendicular magnetic (e.g Co/Cr) or magneto-optic (e.g. Co/Pt) recording media. Of particular concern are the effects of parameters such as crystallographic texture and interface roughness, which are determined by the fabrication conditions, on magnetic properties and structure.In this study we have fabricated Co-based MLF by UHV thermal evaporation in the prechamber of an atom probe field-ion microscope (AP). The multilayers were deposited simultaneously onto cobalt field-ion specimens (for AP and position-sensitive atom probe (POSAP) microanalysis without exposure to atmosphere) and onto the flat (001) surface of oxidised silicon wafers (for subsequent study in cross-section using high-resolution electron microscopy (HREM) in a JEOL 4000EX. Deposi-tion was from W filaments loaded with material in the form of wire (Co, Fe, Ni, Pt and Au) or flakes (Cr). The base pressure in the chamber was around 8×10−8 torr during deposition with a typical deposition rate of 0.05 - 0.2nm/s.

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Harder, Alexander, Mareike Dieding, Volker Walhorn, Sven Degenhard, Andreas Brodehl, Christina Wege, Hendrik Milting, and Dario Anselmetti. "Apertureless scanning near-field optical microscopy of sparsely labeled tobacco mosaic viruses and the intermediate filament desmin." Beilstein Journal of Nanotechnology 4 (September 11, 2013): 510–16. http://dx.doi.org/10.3762/bjnano.4.60.

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Both fluorescence imaging and atomic force microscopy (AFM) are highly versatile and extensively used in applications ranging from nanotechnology to life sciences. In fluorescence microscopy luminescent dyes serve as position markers. Moreover, they can be used as active reporters of their local vicinity. The dipolar coupling of the tip with the incident light and the fluorophore give rise to a local field and fluorescence enhancement. AFM topographic imaging allows for resolutions down to the atomic scale. It can be operated in vacuum, under ambient conditions and in liquids. This makes it ideal for the investigation of a wide range of different samples. Furthermore an illuminated AFM cantilever tip apex exposes strongly confined non-propagating electromagnetic fields that can serve as a coupling agent for single dye molecules. Thus, combining both techniques by means of apertureless scanning near-field optical microscopy (aSNOM) enables concurrent high resolution topography and fluorescence imaging. Commonly, among the various (apertureless) SNOM approaches metallic or metallized probes are used. Here, we report on our custom-built aSNOM setup, which uses commercially available monolithic silicon AFM cantilevers. The field enhancement confined to the tip apex facilitates an optical resolution down to 20 nm. Furthermore, the use of standard mass-produced AFM cantilevers spares elaborate probe production or modification processes. We investigated tobacco mosaic viruses and the intermediate filament protein desmin. Both are mixed complexes of building blocks, which are fluorescently labeled to a low degree. The simultaneous recording of topography and fluorescence data allows for the exact localization of distinct building blocks within the superordinate structures.

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Jiang, Zhaoguo, C. J. Lu, D. B. Bogy, and T. Miyamoto. "Dependence of Nano-Friction and Nano-Wear on Loading Force for Sharp Diamond Tips Sliding on Si, Mn-Zn Ferrite, and Au." Journal of Tribology 117, no. 2 (April 1, 1995): 328–33. http://dx.doi.org/10.1115/1.2831251.

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Microscopic friction and wear were measured on both the original top surfaces and freshly worn surfaces of three solid materials including a silicon wafer, a Mn-Zn ferrite block and an Au film, using a recently developed scanning probe microscope with sharp diamond tips. A critical point was observed on the friction versus normal loading force curve. The critical point divides the friction curve into two distinct regimes: a low friction regime in which the friction coefficients are from 0.03–0.06, and a high friction regime where the friction coefficients are between 0.12 and 0.38 depending on the materials tested and the tips. The critical loads at the critical points are different for different materials and different tips. But the average pressures corresponding to the critical points calculated by the Hertz elastic contact theory for different tips are close to each other for the same material. The freshly worn surfaces have tribological behaviors similar to those of the corresponding original top surfaces. Below the critical load no wear is detectable, whereas above the critical load wear is obtained with the wear depth proportional to the load. The implications are that a no-wear sliding condition is possible, for example in contact recording systems, if the asperity contact loads all remain less than the critical value for the particular sliding system.

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Jia, Xiaoxuan, Joshua H. Siegle, Corbett Bennett, Samuel D. Gale, Daniel J. Denman, Christof Koch, and Shawn R. Olsen. "High-density extracellular probes reveal dendritic backpropagation and facilitate neuron classification." Journal of Neurophysiology 121, no. 5 (May 1, 2019): 1831–47. http://dx.doi.org/10.1152/jn.00680.2018.

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Different neuron types serve distinct roles in neural processing. Extracellular electrical recordings are extensively used to study brain function but are typically blind to cell identity. Morphoelectrical properties of neurons measured on spatially dense electrode arrays have the potential to distinguish neuron types. We used high-density silicon probes to record from cortical and subcortical regions of the mouse brain. Extracellular waveforms of each neuron were detected across many channels and showed distinct spatiotemporal profiles among brain regions. Classification of neurons by brain region was improved with multichannel compared with single-channel waveforms. In visual cortex, unsupervised clustering identified the canonical regular-spiking (RS) and fast-spiking (FS) classes but also indicated a subclass of RS units with unidirectional backpropagating action potentials (BAPs). Moreover, BAPs were observed in many hippocampal RS cells. Overall, waveform analysis of spikes from high-density probes aids neuron identification and can reveal dendritic backpropagation. NEW & NOTEWORTHY It is challenging to identify neuron types with extracellular electrophysiology in vivo. We show that spatiotemporal action potentials measured on high-density electrode arrays can capture cell type-specific morphoelectrical properties, allowing classification of neurons across brain structures and within the cortex. Moreover, backpropagating action potentials are reliably detected in vivo from subpopulations of cortical and hippocampal neurons. Together, these results enhance the utility of dense extracellular electrophysiology for cell-type interrogation of brain network function.

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Grand, László, Anita Pongrácz, Éva Vázsonyi, Gergely Márton, Dorottya Gubán, Richárd Fiáth, Bálint Péter Kerekes, György Karmos, István Ulbert, and Gábor Battistig. "A novel multisite silicon probe for high quality laminar neural recordings." Sensors and Actuators A: Physical 166, no. 1 (March 2011): 14–21. http://dx.doi.org/10.1016/j.sna.2010.12.019.

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Wang, Lei, Jing Wen, CiHui Yang, Shan Gai, and YuanXiu Peng. "The Route for Ultra-High Recording Density Using Probe-Based Data Storage Device." Nano 10, no. 08 (November 23, 2015): 1550118. http://dx.doi.org/10.1142/s1793292015501180.

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Phase-change probe memory using Ge2Sb2Te5 has been considered as one of the promising candidates as next-generation data storage device due to its ultra-high density, low energy consumption, short access time and long retention time. In order to utmostly mimic the practical setup, and thus fully explore the potential of phase-change probe memory for 10 Tbit/in2 target, some advanced modeling techniques that include threshold-switching, electrical contact resistance, thermal boundary resistance and crystal nucleation-growth, are introduced into the already-established electrothermal model to simulate the write and read performance of phase-change probe memory using an optimal media stack design. The resulting predictions clearly demonstrate the capability of phase-change probe memory to record 10 Tbit/in2 density under pico Joule energy within micro second period.

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Takahashi, Hirokazu, Astushi Onoe, Takahito Ono, Yasuo Cho, and Masayoshi Esashi. "High-Density Ferroelectric Recording Using Diamond Probe by Scanning Nonlinear Dielectric Microscopy." Japanese Journal of Applied Physics 45, no. 3A (March 8, 2006): 1530–33. http://dx.doi.org/10.1143/jjap.45.1530.

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GAUD, Pierre, Henri SIBUET, Gérard BARROIS, Anton JAMBRUSIC, and Marcel AUDOIN. "A New Silicon Integrated Head For High Density Magnetic Tape Recording." Journal of the Magnetics Society of Japan 18, S_1_PMRC_94_1 (1994): S1_237–239. http://dx.doi.org/10.3379/jmsjmag.18.s1_237.

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Blanche, Timothy J., Martin A. Spacek, Jamille F. Hetke, and Nicholas V. Swindale. "Polytrodes: High-Density Silicon Electrode Arrays for Large-Scale Multiunit Recording." Journal of Neurophysiology 93, no. 5 (May 2005): 2987–3000. http://dx.doi.org/10.1152/jn.01023.2004.

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We developed a variety of 54-channel high-density silicon electrode arrays (polytrodes) designed to record from large numbers of neurons spanning millimeters of brain. In cat visual cortex, it was possible to make simultaneous recordings from >100 well-isolated neurons. Using standard clustering methods, polytrodes provide a quality of single-unit isolation that surpasses that attainable with tetrodes. Guidelines for successful in vivo recording and precise electrode positioning are described. We also describe a high-bandwidth continuous data-acquisition system designed specifically for polytrodes and an automated impedance meter for testing polytrode site integrity. Despite having smaller interconnect pitches than earlier silicon-based electrodes of this type, these polytrodes have negligible channel crosstalk, comparable reliability, and low site impedances and are capable of making high-fidelity multiunit recordings with minimal tissue damage. The relatively benign nature of planar electrode arrays is evident both histologically and in experiments where the polytrode was repeatedly advanced and retracted hundreds of microns over periods of many hours. It was possible to maintain stable recordings from active neurons adjacent to the polytrode without change in their absolute positions, neurophysiological or receptive field properties.

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Steinmetz, Nicholas A., Cagatay Aydin, Anna Lebedeva, Michael Okun, Marius Pachitariu, Marius Bauza, Maxime Beau, et al. "Neuropixels 2.0: A miniaturized high-density probe for stable, long-term brain recordings." Science 372, no. 6539 (April 15, 2021): eabf4588. http://dx.doi.org/10.1126/science.abf4588.

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Measuring the dynamics of neural processing across time scales requires following the spiking of thousands of individual neurons over milliseconds and months. To address this need, we introduce the Neuropixels 2.0 probe together with newly designed analysis algorithms. The probe has more than 5000 sites and is miniaturized to facilitate chronic implants in small mammals and recording during unrestrained behavior. High-quality recordings over long time scales were reliably obtained in mice and rats in six laboratories. Improved site density and arrangement combined with newly created data processing methods enable automatic post hoc correction for brain movements, allowing recording from the same neurons for more than 2 months. These probes and algorithms enable stable recordings from thousands of sites during free behavior, even in small animals such as mice.

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Barz, Falk, Patrick Ruther, Shoji Takeuchi, and Oliver Paul. "Mechanically Adaptive Silicon-based Neural Probes for Chronic High-resolution Neural Recording." Procedia Engineering 120 (2015): 952–55. http://dx.doi.org/10.1016/j.proeng.2015.08.816.

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Buzsáki, György, and Adam Kandel. "Somadendritic Backpropagation of Action Potentials in Cortical Pyramidal Cells of the Awake Rat." Journal of Neurophysiology 79, no. 3 (March 1, 1998): 1587–91. http://dx.doi.org/10.1152/jn.1998.79.3.1587.

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Buzsáki, György and Adam Kandel. Somadendritic backpropagation of action potentials in cortical pyramidal cells of the awake rat. J. Neurophysiol. 79: 1587–1591, 1998. The invasion of fast (Na+) spikes from the soma into dendrites was studied in single pyramidal cells of the sensorimotor cortex by simultaneous extracellular recordings of the somatic and dendritic action potentials in freely behaving rats. Field potentials and unit activity were monitored with multiple-site silicon probes along trajectories perpendicular to the cortical layers at spatial intervals of 100 μm. Dendritic action potentials of individual layer V pyramidal neurons could be recorded up to 400 μm from the cell body. Action potentials were initiated at the somatic recording site and traveled back to the apical dendrite at a velocity of 0.67 m/s. Current source density analysis of the action potential revealed time shifted dipoles, supporting the view of active spike propagation in dendrites. The presented method is suitable for exploring the conditions affecting the somadendritic propagation action of potentials in the behaving animal.

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Lee, Myung Bok, Motonobu Kourogi, Takashi Yatsui, Kazuo Tsutsui, Nobufumi Atoda, and Motoichi Ohtsu. "Silicon planar-apertured probe array for high-density near-field optical storage." Applied Optics 38, no. 16 (June 1, 1999): 3566. http://dx.doi.org/10.1364/ao.38.003566.

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Wang, Lei, Sidi Gong, Cihui Yang, and Jing Wen. "The Experimental Demonstration of the Optimized Electrical Probe Memory for Ultra-High Density Recording." Recent Patents on Nanotechnology 11, no. 1 (February 2, 2017): 70–74. http://dx.doi.org/10.2174/1872210510666160823163455.

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Lazzari, Jean Pierre. "Single pole, single turn, probe GMR head and micro-actuator for high-density perpendicular recording." Journal of Magnetism and Magnetic Materials 235, no. 1-3 (October 2001): 362–67. http://dx.doi.org/10.1016/s0304-8853(01)00380-8.

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Stiller, Allison, Joshua Usoro, Jennifer Lawson, Betsiti Araya, María González-González, Vindhya Danda, Walter Voit, Bryan Black, and Joseph Pancrazio. "Mechanically Robust, Softening Shape Memory Polymer Probes for Intracortical Recording." Micromachines 11, no. 6 (June 25, 2020): 619. http://dx.doi.org/10.3390/mi11060619.

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While intracortical microelectrode arrays (MEAs) may be useful in a variety of basic and clinical scenarios, their implementation is hindered by a variety of factors, many of which are related to the stiff material composition of the device. MEAs are often fabricated from high modulus materials such as silicon, leaving devices vulnerable to brittle fracture and thus complicating device fabrication and handling. For this reason, polymer-based devices are being heavily investigated; however, their implementation is often difficult due to mechanical instability that requires insertion aids during implantation. In this study, we design and fabricate intracortical MEAs from a shape memory polymer (SMP) substrate that remains stiff at room temperature but softens to 20 MPa after implantation, therefore allowing the device to be implanted without aids. We demonstrate chronic recordings and electrochemical measurements for 16 weeks in rat cortex and show that the devices are robust to physical deformation, therefore making them advantageous for surgical implementation.

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Zheng, Yu-Qing, Yuxin Liu, Donglai Zhong, Shayla Nikzad, Shuhan Liu, Zhiao Yu, Deyu Liu, et al. "Monolithic optical microlithography of high-density elastic circuits." Science 373, no. 6550 (July 1, 2021): 88–94. http://dx.doi.org/10.1126/science.abh3551.

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Polymeric electronic materials have enabled soft and stretchable electronics. However, the lack of a universal micro/nanofabrication method for skin-like and elastic circuits results in low device density and limited parallel signal recording and processing ability relative to silicon-based devices. We present a monolithic optical microlithographic process that directly micropatterns a set of elastic electronic materials by sequential ultraviolet light–triggered solubility modulation. We fabricated transistors with channel lengths of 2 micrometers at a density of 42,000 transistors per square centimeter. We fabricated elastic circuits including an XOR gate and a half adder, both of which are essential components for an arithmetic logic unit. Our process offers a route to realize wafer-level fabrication of complex, high-density, and multilayered elastic circuits with performance rivaling that of their rigid counterparts.

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Matsumoto, T., T. Shimano, H. Saga, H. Sukeda, and M. Kiguchi. "Highly efficient probe with a wedge-shaped metallic plate for high density near-field optical recording." Journal of Applied Physics 95, no. 8 (April 15, 2004): 3901–6. http://dx.doi.org/10.1063/1.1669052.

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Nakagawa, S., K. Hiraide, and M. Naoe. "Development of high density perpendicular magnetic recording system using a probe head of sharpened optical fiber." IEEE Transactions on Magnetics 35, no. 5 (1999): 3130–32. http://dx.doi.org/10.1109/20.801104.

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Polley, Craig M., Warrick R. Clarke, Jill A. Miwa, Michelle Y. Simmons, and Justin W. Wells. "Microscopic four-point-probe resistivity measurements of shallow, high density doping layers in silicon." Applied Physics Letters 101, no. 26 (December 24, 2012): 262105. http://dx.doi.org/10.1063/1.4773485.

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Seidl, Karsten, Stanislav Herwik, Tom Torfs, Herc P. Neves, Oliver Paul, and Patrick Ruther. "CMOS-Based High-Density Silicon Microprobe Arrays for Electronic Depth Control in Intracortical Neural Recording." Journal of Microelectromechanical Systems 20, no. 6 (December 2011): 1439–48. http://dx.doi.org/10.1109/jmems.2011.2167661.

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Sabel, Tina. "Spatial Frequency Response of Epoxy-Based Volume Holographic Recording Material." Molecules 24, no. 6 (March 14, 2019): 1018. http://dx.doi.org/10.3390/molecules24061018.

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Holographic volume phase gratings are recorded in an epoxy-based, free-surface, volume holographic recording material. Light-induced gratings are formed by photo-triggered mass migration caused by component diffusion. The material resolution enables a wide range of pattern spacings, to record both transmission and reflection holograms with many different spatial frequencies. An optimum spatial frequency response is found between the low spatial frequency roll-off and the high spatial frequency cut-off. The influence of the energy density of exposure on the spatial frequency response is investigated. Secondary volume holographic gratings (parasitic gratings) are observed in the high frequency range. The possibility of distinguishing the regular grating from the secondary grating is discussed in the form of probe wavelength detuning.

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Tanaka, Kei, Masamichi Yoshimura, and Kazuyuki Ueda. "High-Resolution Magnetic Force Microscopy Using Carbon Nanotube Probes Fabricated Directly by Microwave Plasma-Enhanced Chemical Vapor Deposition." Journal of Nanomaterials 2009 (2009): 1–4. http://dx.doi.org/10.1155/2009/147204.

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Carbon nanotubes (CNTs) have been successfully grown on the tip apex of an atomic force microscopy (AFM) cantilever by microwave plasma-enhanced chemical vapor deposition (MPECVD). Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal that the diameter of the CNTs is∼30 nm and the magnetic particles with diameter of∼20 nm, which was used as catalyst for the CNT growth, exist on the top. This CNT probe has been applied to magnetic force microscopy (MFM) on the ultrahigh-density magnetic recording media with 1200 kilo flux change per inch (kfci).

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PENG, JIEGANG, S. XUE, Z. YAN, X. WU, and L. ZHAN. "INVESTIGATION OF HIGH-COERCIVITY FePt-C NANOGRANULAR FILMS FOR PERPENDICULAR MAGNETIC RECORDING (PMR) MEDIA." Nano 06, no. 06 (December 2011): 569–74. http://dx.doi.org/10.1142/s179329201100286x.

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In this work, we studied FePt-C nanogranular films for ultrahigh-density perpendicular recording media towards 1 Tbits/in2 because they have high magnetocrystalline anisotropy at its L10-phase. We deposit Fe 52 Pt 48- C 50% (7.2 nm) films on oxidized silicon substrates at 400°C and various Ar pressures. Results show that at the Ar pressure of 0.50 Pa, the FePt-C granular film has the best granular structure and MH loop shape with a perpendicular coercivity of 20 kOe. The average grain size of the optimized film is 6.4 ± 1.5 nm. We studied the thermal stability of the optimized film and obtained the energy barrier Eb of 340kBT at room temperature, meaning excellent thermal stability as magnetic recording media.

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Samsonov, Alexander N., and Khristina V. Samoilova. "High speed video recording system on a chip for detonation jet engine testing." MATEC Web of Conferences 158 (2018): 01028. http://dx.doi.org/10.1051/matecconf/201815801028.

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This article describes system on a chip development for high speed video recording purposes. Current research was started due to difficulties in selection of FPGAs and CPUs which include wide bandwidth, high speed and high number of multipliers for real time signal analysis implementation. Current trend of high density silicon device integration will result soon in a hybrid sensor-controller-memory circuit packed in a single chip. This research was the first step in a series of experiments in manufacturing of hybrid devices. The current task is high level syntheses of high speed logic and CPU core in an FPGA. The work resulted in FPGA-based prototype implementation and examination.

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Seidl, Karsten, Michael Schwaerzle, Istvan Ulbert, Herc P. Neves, Oliver Paul, and Patrick Ruther. "CMOS-Based High-Density Silicon Microprobe Arrays for Electronic Depth Control in Intracortical Neural Recording–Characterization and Application." Journal of Microelectromechanical Systems 21, no. 6 (December 2012): 1426–35. http://dx.doi.org/10.1109/jmems.2012.2206564.

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Lee, Dong Weon, Young Soo Choi, and Il Kweon Oh. "Integrated Tunneling Device for High Sensitive Sensor Applications." Key Engineering Materials 326-328 (December 2006): 317–20. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.317.

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This paper describes an integrated tunneling sensor for applications of an electronic nose and a scanning probe microscope. Ultra-thin silicon dioxide having a thickness of ~2 nm is used as a material of the tunneling sensor. It provides much higher sensitivity in comparison with others sensing methods. The tunneling sensor is placed on a fixed edge where the maximum strain arises. As additional masses or forces are added to the surface of the cantilever, the thickness of the thin silicon dioxide layer is slightly decreased. By using exponential nature of electron tunneling dominated by the thickness of the silicon dioxide it can be used as an ultra-high sensitive sensor. The thin dioxide is fabricated by dry oxidation using a vertical furnace. The cantilever structures are defined by conventional MEMS technologies. Current density of the tunneling sensor is evaluated as a function of voltage and is compared with numerical analysis based on direct tunneling phenomena.

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Cheng, Qilong, Siddhesh V. Sakhalkar, and David B. Bogy. "Direct measurement of disk-to-head back-heating in HAMR using a non-flying test stage." Applied Physics Letters 120, no. 24 (June 13, 2022): 241602. http://dx.doi.org/10.1063/5.0092170.

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Heat assisted magnetic recording, as one of the next generation hard disk drive solutions to high areal density over 1 Tb/in.2, integrates a laser delivery system to facilitate data writing. A laser beam is launched from the recording head and is focused on the recording disk to locally heat the disk (400–500 °C), which is even hotter than the head temperature (150–250 °C). Therefore, understanding the thermal transport between the head and the disk is of great importance. In this paper, we used a non-flying test stage to exclude the strong air cooling caused by the rotating disk and performed the thermal transport experiments across a closing nanoscale air gap on two substrates (silicon wafer and AlMg-substrate disk). The experimental results show that the disk-to-head back-heating from the hot spot on the substrate can be directly measured in the case of the AlMg disk (∼2–10 °C), while the silicon case shows no back-heating due to its high thermal conductivity. It is demonstrated that the experimental setup is useful for thermal transport studies between two macroscopic surfaces and future development of such microelectronic devices.

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Billa, Sanjeev, Yaswanthi Yanamadala, Imran Hossain, Shabnam Siddiqui, Nicolaie Moldovan, Teresa A. Murray, and Prabhu U. Arumugam. "Brain-Implantable Multifunctional Probe for Simultaneous Detection of Glutamate and GABA Neurotransmitters: Optimization and In Vivo Studies." Micromachines 13, no. 7 (June 26, 2022): 1008. http://dx.doi.org/10.3390/mi13071008.

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Imbalances in levels of glutamate (GLU) and gamma-aminobutyric acid (GABA) and their sub-second signaling dynamics occur in several brain disorders including traumatic brain injury, epilepsy, and Alzheimer’s disease. The present work reports on the optimization and in vivo testing of a silicon (Si) multifunctional biosensor probe for sub-second simultaneous real-time detection of GLU and GABA. The Si probe features four surface-functionalized platinum ultramicroelectrodes (UMEs) for detection of GLU and GABA, a sentinel site, and integrated microfluidics for in-situ calibration. Optimal enzyme concentrations, size-exclusion phenylenediamine layer and micro spotting conditions were systematically investigated. The measured GLU sensitivity for the GLU and GABA sites were as high as 219 ± 8 nA μM−1 cm−2 (n = 3). The measured GABA sensitivity was as high as 10 ± 1 nA μM−1 cm−2 (n = 3). Baseline recordings (n = 18) in live rats demonstrated a useful probe life of at least 11 days with GLU and GABA concentrations changing at the levels of 100′s and 1000′s of μM and with expected periodic bursts or fluctuations during walking, teeth grinding and other activities and with a clear difference in the peak amplitude of the sensor fluctuations between rest (low) and activity (higher), or when the rat was surprised (a reaction with no movement). Importantly, the probe could improve methods for large-scale monitoring of neurochemical activity and network function in disease and injury, in live rodent brain.

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Talbert, James N., Samuel R. Cantrell, Md Abdul Ahad Talukder, Luisa M. Scolfaro, and Wilhelmus J. Geerts. "Electrical Characterization of Silicon - Nickel Iron Oxide Heterojunctions." MRS Advances 4, no. 41-42 (2019): 2241–48. http://dx.doi.org/10.1557/adv.2019.321.

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ABSTRACTThe electrical properties of Radio Frequency Sputtered NiFeO and NiO films deposited on n and p-type Silicon is investigated for two different oxygen flows. Rectifying properties for Ni0.8Fe0.2O1+ α on n-Si showed Iforward/Ireverse >10,000 for α>0 and Iforward/Ireverse >50 for α<0. Both types of devices have opposite forward biases. Results suggest that NiFeO sputtered at high oxygen flow is p-type. For NiO and NiFeO on p-Si no strong rectifying properties were observed. The specific contact resistivity of Pt/Ni0.9Fe0.1O1+ α (α>0) was estimated from the difference between the two and four-point probe resistances (0.0007 ± 0.0003 Ω cm2). Using density functional theory calculations, density of state and charge density plots were obtained for systems modelled after experiment, showing that states introduced by O vacancies in NiFeO are localized and prefer locations near Ni explaining the observed hysteresis effects in the IV curves of devices sputtered at low oxygen flow.

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Ventimiglia, Giorgio, Massimiliano Pesaturo, Alastair Malcolm, and Salvatore Petralia. "A Miniaturized Silicon Lab-on-Chip for Integrated PCR and Hybridization Microarray for High Multiplexing Nucleic Acids Analysis." Biosensors 12, no. 8 (July 25, 2022): 563. http://dx.doi.org/10.3390/bios12080563.

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A silicon lab-on-chip, for the detection of nucleic acids through the integrated PCR and hybridization microarray, was developed. The silicon lab-on-chip manufactured through bio-MEMS technology is composed of two PCR microreactors (each volume 11.2 µL) and a microarray-hybridization microchamber (volume 30 µL), fluidically connected by buried bypass. It contains heaters and temperature sensors for the management and control of the temperature cycles during the PCR amplification and hybridization processes. A post-silicon process based on (i) plasmo-O2 cleaning/activation, (ii) vapor phase epoxy silanization, (iii) microarray fabrication and (iv) a protein-based passivation step was developed and fully characterized. The ssDNA microarray (4 rows × 10 columns) composed of 400 spots (spot size—70 ± 12 µm; spot-to-spot distance—130 ± 13 µm) was manufactured by piezo-dispense technology. A DNA microarray probe density in the range of 1310 to 2070 probe µm−2 was observed, together with a limit of detection of about 19 target µm−2. The performances of the silicon lab-on-chip were validated by the detection of the beta-globin gene directly from human blood. Remarkable sensitivity, multiplexing analysis and specificity were demonstrated for the detection of beta-globin and mycobacterium tuberculosis sequences.

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Journal articles on the topic 'High-density silicon probe recording'

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