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Publications (10 of 156) Show all publications
Xu, Z., Yu, Y., Paul, S. & Zhang, Z. (2025). Integration of AC bias-stabilized SiNRFETs with microscale Ag/AgCl pseudo-reference electrodes for lab-on-chip biosensing application. Sensors and actuators. B, Chemical, 441
Open this publication in new window or tab >>Integration of AC bias-stabilized SiNRFETs with microscale Ag/AgCl pseudo-reference electrodes for lab-on-chip biosensing application
2025 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 441Article in journal (Refereed) Published
Abstract [en]

Ion-sensitive field-effect transistors (ISFETs) are highly promising for lab-on-chip integration due to their excellent scalability, high sensitivity, and rapid response times. However, on-chip integration of reliable microscale reference electrodes, essential for ISFET operation in microfluidic systems, remains a significant challenge. This study presents a microfluidic pH meter that integrates silicon nanoribbon field-effect transistor (SiNRFET) sensors with on-chip microscale AgCl/Ag pseudo-reference electrodes (p-REs). The microscale p-REs, fabricated using CMOS-compatible processes and protected with a photoresist layer, demonstrated rapid stabilization and long-term stability. Moreover, the short distance between the integrated p-REs and the paired SiNRFET sensors within the microfluidic environment minimized streaming potential, ensuring measurement accuracy regardless of flow rate variations. In addition, applying an AC pulse gate bias effectively reduced ISFET signal drift caused by ion penetration into the pH-sensitive layer, enhancing the system's reliability for long-term monitoring. To showcase the platform’s biosensing capabilities, the microfluidic pH meter was finally used to monitor bacterial metabolism on-chip via measuring pH changes induced by metabolic activity with microliter-level samples. This work establishes a robust lab-on-chip biosensing platform, enabling real-time and long-term biosensing in microscale environments.

Place, publisher, year, edition, pages
Elsevier, 2025
Keywords
AgCl/Ag pseudo-reference electrode, On-chip integration, Ion-sensitive field-effect transistors, Microfluidics, Drift, AC pulse gate bias
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Nanotechnology for/in Life Science and Medicine
Research subject
Engineering Science with specialization in Electronics; Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-556983 (URN)10.1016/j.snb.2025.138000 (DOI)001499471300003 ()2-s2.0-105005596429 (Scopus ID)
Projects
Swedish Strategic Research Foundation under Grant SSF FFL15-0174Wallenberg Academy Fellow Program under Grant KAW 2020-0190Stiftelsen Olle Engkvist under Postdoc grant 214-0322
Funder
Swedish Research Council, 2019-04690Swedish Foundation for Strategic Research, SSF FFL15-0174Knut and Alice Wallenberg Foundation, 2020-0190Olle Engkvists stiftelse, 214-0322
Available from: 2025-05-20 Created: 2025-05-20 Last updated: 2025-06-17
Xu, Z., Chen, S., Hu, Q., Zhang, S.-L. & Zhang, Z. (2024). A Nanoribbon-Based Ion-Gated Lateral Bipolar Amplifier for Ion Sensing. IEEE Transactions on Electron Devices, 71(7), 4362-4367
Open this publication in new window or tab >>A Nanoribbon-Based Ion-Gated Lateral Bipolar Amplifier for Ion Sensing
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2024 (English)In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 71, no 7, p. 4362-4367Article in journal (Refereed) Published
Abstract [en]

Nanoscale sensors usually produce feeble signals susceptible to inevitable external interference. Several signal amplification solutions exist for mitigating the interference. However, most nanoscale sensors are fabricated on silicon-on-insulator (SOI) substrate, which is not compatible with the integration process of traditional vertical bipolar amplifiers. This work presents an ion-gated lateral bipolar amplifier that integrates a nanoribbon filed-effect transistor (NRFET) ion sensor with a lateral bipolar junction transistor (LBJT), all on an SOI substrate, thereby greatly simplifying the fabrication process. The direct connection between the LBJT base and the NRFET source enables immediate amplification of the NRFET signal, minimizing exposure to surrounding interference. Characterized by a peak current gain exceeding 20, this amplifier design leads to a 3–7-fold enhancement in the overall signal-to-noise ratio (SNR) compared to a reference NRFET. Furthermore, this gain in SNR is empirically validated during pH sensing applications. The possibility of substrate biasing makes the integrated LBJT-NRFET amplifier unique as it can independently tune the current gain and reduce the noise thereby improving the SNR performance.

Place, publisher, year, edition, pages
IEEE, 2024
Keywords
CMOS compatibility, internal signal amplification, lateral bipolar junction transistors (LBJTs), lowfrequency noise, nanoribbon-based field-effect transistors, pH sensor.
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics; Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-530929 (URN)10.1109/ted.2024.3400926 (DOI)001230781700001 ()
Projects
Swedish Strategic Research Foundation under Grant SSF FFL15-0174Wallenberg Academy Fellow Program under Grant KAW 2020-0190
Funder
Swedish Research Council, VR 2019-04690
Available from: 2024-06-10 Created: 2024-06-10 Last updated: 2024-11-29Bibliographically approved
Zhu, Y., Liang, J.-s., Shi, X. & Zhang, Z. (2024). Interface Resistance-Switching with Reduced Cyclic Variations for Reliable Neuromorphic Computing. Journal of Physics D: Applied Physics, 57(7), Article ID 075105.
Open this publication in new window or tab >>Interface Resistance-Switching with Reduced Cyclic Variations for Reliable Neuromorphic Computing
2024 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 57, no 7, article id 075105Article in journal (Refereed) Published
Abstract [en]

As a synaptic device candidate for artificial neural networks (ANNs), memristors hold great promise for efficient neuromorphic computing. However, commonly used filamentary memristors normally exhibit large cyclic variations due to the stochastic nature of filament formation and ablation, which will inevitably degrade the computing accuracy. Here we demonstrate, in nanoscale Ag2S-based memristors that resistance-switching (RS) at the contact interface can be a promising solution to reduce cyclic variations. When the Ag2S memristor is operated with a filament-free interface RS via Schottky barrier height modification at the contact interface, it shows an ultra-small cycle-to-cycle variation of 1.4% during 104 switching cycles. This is in direct contrast to the variation of (28.9%) of the RS filament extracted from the same device. Interface RS can also emulate synaptic functions and psychological behavior. Its improved learning ability over a filament RS, with a higher saturated accuracy approaching 99.6%, is finally demonstrated in a simplified ANN.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2024
Keywords
Ag2S, interface resistance-switching, Schottky barrier modification, cyclic variation, image learning
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-516290 (URN)10.1088/1361-6463/ad0b52 (DOI)001108043500001 ()
Funder
Swedish Foundation for Strategic Research, FFL15-0174Swedish Research Council, VR 2018-06030Knut and Alice Wallenberg Foundation, KAW 2015-0127Knut and Alice Wallenberg Foundation, 2020-0190
Available from: 2023-11-20 Created: 2023-11-20 Last updated: 2023-12-15Bibliographically approved
Hu, Q., Solomon, P., Österlund, L. & Zhang, Z. (2024). Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles. Nature Communications, 15(1), Article ID 5259.
Open this publication in new window or tab >>Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles
2024 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 15, no 1, article id 5259Article in journal (Refereed) Published
Abstract [en]

Highly sensitive, low-power, and chip-scale H2 gas sensors are of great interest to both academia and industry. Field-effect transistors (FETs) functionalized with Pd nanoparticles (PdNPs) have recently emerged as promising candidates for such H2 sensors. However, their sensitivity is limited by weak capacitive coupling between PdNPs and the FET channel. Herein we report a nanoscale FET gas sensor, where electrons can tunnel between the channel and PdNPs and thus equilibrate them. Gas reaction with PdNPs perturbs the equilibrium, and therefore triggers electron transfer between the channel and PdNPs via trapping or de-trapping with the PdNPs to form a new balance. This direct communication between the gas reaction and the channel enables the most efficient signal transduction. Record-high responses to 1–1000 ppm H2 at room temperature with detection limit in the low ppb regime and ultra-low power consumption of ∼300 nW are demonstrated. The same mechanism could potentially be used for ultrasensitive detection of other gases. Our results present a supersensitive FET gas sensor based on electron trapping effect in nanoparticles.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Gas sensing, nanotransistor, electrion trapping effect, PdNPs
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-532977 (URN)10.1038/s41467-024-49658-3 (DOI)001252637700003 ()38898091 (PubMedID)2-s2.0-85196372507 (Scopus ID)
Projects
Swedish Strategic Research Foundation FFL15-0174Wallenberg Academy Fellow KAW2015-0127Wallenberg Academy Fellow KAW2020-0190H2020-MSCA-RISE program through “Canleish” 101007653Olle Engkvist Foundation 196-0077
Funder
Swedish Foundation for Strategic Research, FFL15-0174Swedish Research Council, 2014-05588Swedish Research Council, 2019-04690Knut and Alice Wallenberg Foundation, 2015-0127Knut and Alice Wallenberg Foundation, 2020-0190EU, Horizon 2020, 101007653Olle Engkvists stiftelse, 196-0077Uppsala University
Available from: 2024-06-24 Created: 2024-06-24 Last updated: 2025-02-19Bibliographically approved
Zhu, Y., Nyberg, T., Nyholm, L., Primetzhofer, D., Shi, X. & Zhang, Z. (2024). Wafer-Scale Ag2S-based Memristive Crossbar Arrays with Ultra-low Switching-energies Reaching Biological Synapses. Nano-Micro Letters, 17, Article ID 69.
Open this publication in new window or tab >>Wafer-Scale Ag2S-based Memristive Crossbar Arrays with Ultra-low Switching-energies Reaching Biological Synapses
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2024 (English)In: Nano-Micro Letters, ISSN 2150-5551, Vol. 17, article id 69Article in journal (Refereed) Published
Abstract [en]

Memristive crossbar arrays (MCAs) offer parallel data storage and processing for energy-efficient neuromorphic computing. However, most wafer-scale MCAs that are compatible with complementary metal–oxide–semiconductor (CMOS) technology still suffer from substantially larger energy consumption than biological synapses, due to the slow kinetics of forming conductive paths inside the memristive units. Here we report wafer-scale Ag2S-based MCAs realized using CMOS-compatible processes at temperatures below 160 oC. Ag2S electrolytes supply highly mobile Ag+ ions, and provide the Ag/Ag2S interface with low silver nucleation barrier to form silver filaments at low energy costs. By further enhancing Ag+ migration in Ag2S electrolytes via microstructure modulation, the integrated memristors exhibit a record low threshold of approximately -0.1 V, and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses. The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics. Moreover, the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm. An impressive accuracy of 92.6 % in image recognition simulations is demonstrated with the MCAs after the compensation. The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.  

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Wafer-scale Ag2S films, Reactive sputter, Silver nucleation, Ag+ migration, Energy- efficient neuromorphic computing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-542285 (URN)10.1007/s40820-024-01559-2 (DOI)001361606100001 ()39572441 (PubMedID)2-s2.0-85209734599 (Scopus ID)
Funder
Swedish Foundation for Strategic Research, FFL15-0174Swedish Research Council, 2018-06030Swedish Research Council, 2019-04690Knut and Alice Wallenberg Foundation, 2020-0190Olle Engkvists stiftelse, 214-0322
Available from: 2024-11-10 Created: 2024-11-10 Last updated: 2025-01-14Bibliographically approved
Zhang, Z. (2023). A device, a system and a method for performing antibiotic susceptibility tests. se 2350054-9.
Open this publication in new window or tab >>A device, a system and a method for performing antibiotic susceptibility tests
2023 (English)Patent (Other (popular science, discussion, etc.))
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-498912 (URN)
Patent
SE 2350054-9 (2023-01-23)
Available from: 2023-03-21 Created: 2023-03-21 Last updated: 2023-03-21
Nemouchi, F., Lefloch, F., Zhang, S.-L. & Zhang, Z. (2023). Method for producing a superconducting transistor. fr EP23305137.4.
Open this publication in new window or tab >>Method for producing a superconducting transistor
2023 (English)Patent (Other (popular science, discussion, etc.))
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-498911 (URN)
Patent
FR EP23305137.4 (2023-02-02)
Available from: 2023-03-21 Created: 2023-03-21 Last updated: 2023-03-21
Yu, Y., Gauthier, N., Primetzhofer, D. & Zhang, Z. (2023). Shallow junction formation via lateral boron autodoping during rapid thermal process [Letter to the editor]. Journal of Physics D: Applied Physics, 56(45), 45LT01
Open this publication in new window or tab >>Shallow junction formation via lateral boron autodoping during rapid thermal process
2023 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 56, no 45, p. 45LT01-Article in journal, Letter (Other academic) Published
Abstract [en]

Autodoping is a well-known phenomenon of unwanted dopant transfer in silicon epitaxy process. In this work, we discovered boron lateral autodoping in normal rapid thermal process (RTP) and used it to controllably form shallow junctions for device fabrication. The redeposition of boron from the gas phase to the solid surface was identified to be the limiting step of the boron incorporation into the undoped silicon area in the RTP process. At a given RTP temperature, boron autodoping could be increased by elevating the concentration of the boron source or enhancing the evaporation coefficient. Extending the annealing time can substantially improve the uniformity of the boron concentration in the gas phase, thus reducing the pattern dependence of the autodoping results. In addition, the autodoping process also avoids the traps and defects induced by ion implantation. Therefore, the described mechanism holds great promise for shallow junction formation in selectively patterned area with low cost.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2023
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-508700 (URN)10.1088/1361-6463/acec87 (DOI)001168945000001 ()
Funder
Knut and Alice Wallenberg Foundation, 2020-0190Swedish Research Council, 2019-00191Swedish Research Council, 2019-00207Swedish Research Council, 2019-04690Swedish Research Council, VR-RFI 2017-00646-9
Available from: 2023-08-07 Created: 2023-08-07 Last updated: 2024-03-15Bibliographically approved
Zando, R., Chinappi, M., Giordani, C., Cecconi, F. & Zhang, Z. (2023). Surface-particle interactions control the escape time of a particle from a nanopore-gated nanocavity system: a coarse grained simulation. Nanoscale, 15(26), 11107-11114
Open this publication in new window or tab >>Surface-particle interactions control the escape time of a particle from a nanopore-gated nanocavity system: a coarse grained simulation
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2023 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 15, no 26, p. 11107-11114Article in journal (Refereed) Published
Abstract [en]

Nanopores and nanocavities are promising single molecule tools for investigating the behavior of individual molecules within confined spaces. For single molecule analysis, the total duration of time the analyte remains within the pore/cavity is highly important. However, this dwell time is ruled by a complex interplay among particle–surface interactions, external forces on the particle and Brownian diffusion, making the prediction of the dwell time challenging. Here, we show how the dwell time of an analyte in a nanocavity that is connected to the external environment by two nanopore gates depends on the sizes of the nanocavity/nanopore, as well as particle–wall interactions. For this purpose, we used a coarse-grained model that allowed us to simulate hundreds of individual analyte trajectories within a nanocavity volume. We found that by increasing the attraction between the particle and the wall, the diffusion process transforms from a usual 3D scenario (repulsive wall) to a 2D motion along the cavity surface (highly attractive wall). This results in a significant reduction of the average dwell time. Additionally, the comparison of our results with existing theories on narrow escape problem allowed us to quantify the reliability of theory derived for ideal conditions to geometries more similar to actual devices.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2023
National Category
Nano Technology Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-505197 (URN)10.1039/d3nr01329d (DOI)001010836400001 ()
Available from: 2023-06-19 Created: 2023-06-19 Last updated: 2023-10-11Bibliographically approved
Xu, X., Chen, S., Yu, Y., Virtanen, P., Wu, J., Hu, Q., . . . Zhang, Z. (2022). All-electrical antibiotic susceptibility testing within 30 min using silicon nano transistors. Sensors and actuators. B, Chemical, 357, Article ID 131458.
Open this publication in new window or tab >>All-electrical antibiotic susceptibility testing within 30 min using silicon nano transistors
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2022 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 357, article id 131458Article in journal (Refereed) Published
Abstract [en]

Rapid and reliable antibiotic susceptibility testing (AST) platform is highly desired to select the right antibiotics to treat infectious disease at early stage. Here, we demonstrate rapid ASTs using nanoscale silicon ion-selective field-effect transistor sensors. Our sensors profile bacterial metabolic kinetics by monitoring the metabolism induced acidification in the growth media with the absence and the presence of different antibiotics. Rapid AST results could be determined from the metabolic profiles with a total assay time less than 30 min for different bacterial strains. In addition, the sensors could also distinguish the bactericidal mechanisms for antibiotics with different modes of actions. Furthermore, the initial bacterial concentration in an unknown sample, a key parameter to determine its clinic relevance, could be estimated based on the metabolic profiles. Our demonstrated AST method is all-electrical, label-free and silicon technology compatible, and holds great promise for the development of a high-throughput and low-cost point-of-care device.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Antibiotic susceptibility testing, Point of care, Minimal inhibitory concentration, Ion-selective field-effect transistor, Cell metabolism
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-486692 (URN)10.1016/j.snb.2022.131458 (DOI)000860630400006 ()
Funder
Swedish Foundation for Strategic Research, FFL15-0174Swedish Research Council, 2019-04690Olle Engkvists stiftelse, 1960077Knut and Alice Wallenberg Foundation, 2015-0127
Available from: 2022-10-17 Created: 2022-10-17 Last updated: 2023-10-31Bibliographically approved
Projects
Nanowire-IGBA sensor technology for single-charge detection [2014-05588_VR]; Uppsala University; Publications
Hu, Q., Solomon, P., Österlund, L. & Zhang, Z. (2024). Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles. Nature Communications, 15(1), Article ID 5259.
Travel grant to Future Leaders´ Program of STS forum [2017-03434_Vinnova]; Uppsala UniversityHigh-performance Flexible Thermoelectric Materials and Devices [2018-06030_VR]; Uppsala University; Publications
Zhu, Y., Nyberg, T., Nyholm, L., Primetzhofer, D., Shi, X. & Zhang, Z. (2024). Wafer-Scale Ag2S-based Memristive Crossbar Arrays with Ultra-low Switching-energies Reaching Biological Synapses. Nano-Micro Letters, 17, Article ID 69. Zhu, Y., Liang, J.-s., Shi, X. & Zhang, Z. (2022). Full-Inorganic Flexible Ag2S Memristor with Interface Resistance–Switching for Energy-Efficient Computing. ACS Applied Materials and Interfaces, 14(38), 43482-43489
A novel low noise Si nano-sensor for rapid antibiotic susceptibility tests [2019-04690_VR]; Uppsala University; Publications
Xu, Z., Yu, Y., Paul, S. & Zhang, Z. (2025). Integration of AC bias-stabilized SiNRFETs with microscale Ag/AgCl pseudo-reference electrodes for lab-on-chip biosensing application. Sensors and actuators. B, Chemical, 441Xu, Z., Chen, S., Hu, Q., Zhang, S.-L. & Zhang, Z. (2024). A Nanoribbon-Based Ion-Gated Lateral Bipolar Amplifier for Ion Sensing. IEEE Transactions on Electron Devices, 71(7), 4362-4367Hu, Q., Solomon, P., Österlund, L. & Zhang, Z. (2024). Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles. Nature Communications, 15(1), Article ID 5259. Zhu, Y., Nyberg, T., Nyholm, L., Primetzhofer, D., Shi, X. & Zhang, Z. (2024). Wafer-Scale Ag2S-based Memristive Crossbar Arrays with Ultra-low Switching-energies Reaching Biological Synapses. Nano-Micro Letters, 17, Article ID 69.
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