We systematically investigate the interplay between materials engineering, quantum transport, and low-frequency charge noise in silicon metal–oxide–semiconductor (SiMOS) quantum devices. By combining Hall-bar transport measurements with charge-noise spectroscopy of gate-defined quantum dots, we identify correlations between gate-stack design, carrier mobility, and electrostatic noise, providing an experimental case study of material and process dependencies relevant to low-noise, high-mobility operation. Hall-bar studies reveal that increasing the atomic-layer-deposition temperature of Al_2O_3 markedly enhances mobility, whereas the choice of oxidant has little impact. Devices incorporating HfO_2 exhibit improved carrier mobility, an interesting observation that can plausibly be attributed to defect passivation associated with aluminum diffusion from the gate metal into the HfO_2 layer. Charge-noise measurements show a strong correlation between higher mobility and reduced noise, with TiPd-gated devices displaying both degraded transport and elevated charge noise. In contrast, the poly-Si-gated CMOS-foundry device achieves the lowest noise levels. Finally, dual-feedback dot–sensor stability mapping demonstrates enhanced charge stability in devices with the gate stacks studied here, underscoring their promise for scalable, high-fidelity silicon spin-qubit platforms.

The realization of large-scale silicon quantum processors requires spin qubits compatible with advanced semiconductor manufacturing technologies, demanding lithographic processes that combine nanometer-scale precision with exceptional uniformity. Although the highest-performing silicon spin qubits demonstrated to date have relied on electron-beam (e-beam) lithography, its serial exposure process limits reproducibility studies and wafer-scale fabrication. Here, we demonstrate high-performance silicon metal-oxide-semiconductor (SiMOS) spin qubits fabricated using extreme-ultraviolet (EUV) lithography in a 300 mm semiconductor pilot line. We report wafer-scale quantum-dot uniformity metrics, including 100

Heterogeneous integration provides a promising route to combine semiconductor quantum dot devices and superconducting microwave circuits, while allowing each component to be fabricated using an optimized process flow. Here, we demonstrate a flip-chip integrated platform for dispersive readout of silicon metal-oxide semiconductor (SiMOS) quantum dot devices. A SiMOS double quantum dot chip is bonded to a superconducting aluminum resonator chip using indium bump interconnects to enable microwave coupling to the quantum dot gate. We show that the developed flip-chip process is compatible with cryogenic operation of both the SiMOS device and the superconducting resonator, and demonstrate resonator-based detection of charge transitions in the quantum dot system. The readout signal-to-noise ratio follows a dependence of √(t) with the integration time, reaching SNR = 1 at an integration time of approximately 0.3 ms. These results establish flip-chip bonding as a viable integration approach for SiMOS quantum dot devices operating at both dc and microwave frequencies, with potential applications for resonator-based techniques such as spin-photon coupling.

Many technologies require a precise electrical current standard that at present is achieved indirectly through voltage and resistance standards. Silicon-based charge pumps could provide a direct electrical standard that scales inherently through their compatibility with complementary metal oxide semiconductor (CMOS) fabrication methods. However, coherent quantized charge transfer has so far been demonstrated only in nanoscale devices that are custom-fabricated in academic cleanrooms or research technology foundries. Here, we show that a CMOS device manufactured with a commercial 22 nm process node can be used to realize a quantum current standard in the International System of Units (SI). We measure the accuracy of two parallel-connected charge pumps with reference to SI-traceable voltage and resistance standards in a pumped helium system. This translation of low-temperature quantum effect device concepts from scientific research into an industrial fabrication context opens a path toward advancing quantum electrical metrology and quantum hardware engineering.

Spin shuttling offers a promising approach for developing scalable silicon-based quantum processors by addressing the connectivity limitations of quantum dots. In this work, we demonstrate high-fidelity bucket-brigade spin shuttling in a silicon MOS device, utilizing Pauli-spin-blockade readout. We achieve an average shuttling fidelity of 99.8%. The residual shuttling error is highly sensitive to the ratio between interdot tunnel coupling and Zeeman splitting, with tuning of these parameters enabling up to a 20-fold variation in error rate. An appropriate four-level Hamiltonian model supports our findings. These results provide valuable insights for optimizing high-performance spin-shuttling systems in future quantum architectures.

Achieving an ultra-broad spectral response in a self-bias detector is a formidable challenge that persists in optoelectronics that necessitates innovative solutions. We propose a unique ultra-broadband photodetecting device, utilizing a multilayer structure comprising Molybdenum Di-sulfide (MoS2), Antimony Tri-selenide (Sb2Se3), and Gallium Nitride (GaN), which exhibits the unique capability of detecting photons without applied bias. The fabricated device demonstrates exceptional sensitivity to a wide range of illumination wavelengths, spanning from ultraviolet-C (UV-C) to infrared-B (IR-B). The design detector displays the highest photo-responsivity of 665 mAW(-1) in photovoltaic mode and 3.89 x 10(5) mAW(-1) in photoconductive mode. The designed detector also exhibits a minimal dark current of 90 nA and an extremely weak signal detection capability of similar to 12 femto watt-hertz(-1/2) at 6 V bias. Additionally, the thermal stability of the MoS2-Sb2Se3-GaN (Mo-Sb-Ga) multi-layer-based self-bias detector was explored. Under the self-bias conditions, the photodetector exhibits a stable behavior up to 250 degrees C with a peak responsivity of 635 mAW(-1). The thermal durability of the self-bias ultra-broadband photodetector indicates excellent potential for developing futuristic optoelectronic devices. Further, the performance of the developed detector was examined using Technology Computer-Aided Design (TCAD) simulations, providing valuable insights into the device behavior and the transport of photo-generated carriers, enhancing our understanding of the device operation and enabling performance optimization for diverse applications.

The evolution of computers from room-sized, sophisticated machines to compact, affordable tabletop devices, could serve as a compelling analogy for progress in the electrical metrology. Precise low-current metrology has become increasingly important due to the growing demands for accurate radiation monitoring, energy usage assessment, X-ray and gamma ray based medical instrumentation, and air pollution mapping. In the CGPM redefinition of the ampere, three ways have been proposed for the realization of the SI unit for electric current. Significant research has been pursued by national measurement institutes (NMI), industries and academia to realize an accurate benchmark current. However, these running measurement systems are immobile, sophisticated and expensive since its operation requires dilution refrigerator, and room-temperature control-readout electronics. Utilising the scale of the complementary metal oxide semiconductor (CMOS) industry to produce commercial nanoscopic devices has been a long-standing goal of many research efforts. One of the goals is to realize the quantum ampere, which can be used for the realization of SI ampere. Here, we operate a device made in a commercial 22-nm node Fully depleted silicon on insulator (FDSOI) CMOS— the technology used in mobile phones and computers, to generate a quantized reference current by transferring single electrons. This is also one of the CGPM suggestions for the direct realisation of the SI ampere. We simultaneously pumped single electrons across two parallel devices on the same chip, up to a frequency of 50 MHz in a simple pumped helium system. Future aim includes implementation of this technology to realize a portable table-top cryogenic dc-source-module that incorporates several charge pumps in parallel along with the electrical circuitry on a single-chip to generate metrologically relevant current. This would pave the way for a transportable and scalable primary SI ampere standard by use of CMOS technology, which is well-established across semiconductor foundries.

High-performance broadband photodetectors are widely studied due to their unique significance in military and industrial applications. Vander Waals materials-based detector that simultaneously achieves a fast and high response are prerequisites for expanding the current capabilities of the optoelectronic device. Yet the thermal stability of the Vander Waals materials-based broadband (450 nm to 1250 nm) device is rarely addressed. Here, an antimony selenide (Sb2Se3) based photodetector is reported, which reveals high photo-responsivity and detectivity up to 924 mAW-1 (346 mAW-1) and 2.7 x 1010 Jones (1.0 x 1010 Jones) for the illumination wavelength 1064 nm (532 nm) under photovoltaic mode. Moreover, under 0 V-applied bias condition, the developed detector thermal stability was tested, and up to 100 degrees C devices disclosed a stable behavior. Further, the fabricated Sb2Se3-based broadband device was also tested under photoconductive mode. The photodetector demonstrates high responsivities of 1.5 x 104 mAW-1 (1.3 x 104 mAW-1) and 4.1 x 104 mAW-1 (3.8 x 104 mAW-1) for the illumination wavelength 532 nm and 1064 nm, respectively at room temperature (100 degrees C) under 0.5 V applied bias condition and 1 mu W optical power. The design device can offer ideas for constructing high thermal stability and encouraging such materials in broadband photodetector applications. The state-of-the-art Sb2Se3-based detector can facilitate the translation of solution-processed optoelectronic applications from the laboratory to the marketplace.

Semiconductor tunable barrier single-electron pumps can produce output current of hundreds of picoamperes at sub ppm precision, approaching the metrological requirement for the direct implementation of the current standard. Here, we operate a silicon metal-oxide-semiconductor electron pump up to a temperature of 14 K to understand the temperature effect on charge pumping accuracy. The uncertainty of the charge pump is tunnel limited below liquid helium temperature, implying lowering the temperature further does not greatly suppress errors. Hence, highly accurate charge pumps could be confidently achieved in a $^4$He cryogenic system, further promoting utilization of the revised quantum current standard across the national measurement institutes and industries worldwide.

The direct realization of the ampere in the International System of Units is based on precise control of electron transport across a quantum dot to generate an accurate benchmark current. Practical implementation of this technology for dc-current metrology demands an output current of at least hundreds of microamperes within a relative uncertainty below sub-parts-per-million. Here, we propose a physical architecture of a cryogenic dc-source-module that incorporates several charge-pumps in parallel on a single-chip to potentially fulfill the metrological requirement. The total current produced by the dc-source-module is given by the summation of the quantized current collected from individual charge-pumps while transferring single-electrons per voltage cycle.

After the enormous success of graphene, researchers have been extensively searching for similar materials to explore potential future insights for nanotechnology applications. In 2015, an emerging material called borophene was synthesized on an Ag substrate. Because of the unique physical and electronic properties of borophene, it has been recognized as a prospective material for the advancement of cutting-edge technology. In this review, we have summarized the computational study of one of the most promising gas-capture materials, borophene, i.e., the gas adsorption of gases such as sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), hydrogen cyanide (HCN), methanal (HCOH), adenine (AD), dimethylamine (DMA), trimethylamine (TMA), nitric oxide (NO), ammonia (NH3), and nitrogen dioxide (NO2), and volatile organic compounds (VOCs) like benzene (C6H6), ethylene (C2H4), ethane (C2H6), toluene (Ph-CH3), methanol (H3COH), methyl chloride (H3CCl), formic acid (HCOOH), and formaldehyde (H2CO) on the borophene surface using density functional theory (DFT). Furthermore, in the abovementioned study, the adsorption energy(E-ad) and the density of states (DOS) of the respective gases are explained.

Achieving broadband self-powered photoresponse by a single device remains a top priority in the scientific community. Van der Waals (vdW) heterostructures, a lattice-matched structure, have great potential for self-powered broadband optoelectronic devices. Herein, a MoS2/Sb2Se3 heterostructure broadband photodetector is proposed, which can work in spectral range visible (Vis) to infrared-B (IR-B). The built device exhibited a strong built-in potential, resulting in the device displaying excellent responsivity 42 mAW(-1), 125 mAW(-1), and 60 mAW(-1) for Vis (532 nm), IR-A (1064 nm), and IR-B (1405 nm) light illumination, respectively, under self-powered mode at room temperature. Moreover, the performance of the photodetector is also supported by the technology computer-aided design (TCAD) simulation insights. In addition, the fabricated vdW heterostructure-based device exhibited a stable response at high-temperature (125 degrees C) conditions and displayed peak responsivity 116 mAW(-1) for the IR-A illumination. The fabricated detector is also tested in photoconductive mode, where the computed value of peak state-of-art metrics are responsivity (1.3 x 10(4) mAW(-1)), detectivity (3.89 x 10(10) Jones), and quantum efficiency (1.5 x 10(3)%) at 0.8 V bias and a weak 5 mu W optical power. Along with this, the device is able to detect a very faint optical signal of similar to 300 femto-watt. Hence, the proposed MoS2/Sb2Se3 van der Waals heterostructure-based device provides an enforceable pathway toward achieving self-powered technology, opening avenues for its application across a broad spectrum of optoelectronics.

Thin HfTiOx high-k gate dielectric (Ti ~26.6%) has been sputter-deposited on strained Si0.81Ge0.19 heterolayers. The energy band discontinuities and interface properties were studied using X-ray photoelectron spectroscopy. The conduction band offset, and valance band offset between HfTiOx and Si0.81Ge0.19 were found to be 1.34 and 2.52 eV, respectively. Further, temperature-dependent (300–500 K) current density–voltage measurements (J–V) were utilized to explore the underlying leakage current conduction mechanism. The conductive dislocation and emission barrier heights at the hetero-interface have also been extracted from temperature-dependent J–V measurement. The barrier height of 1.22 to 2.02 eV for Schottky emission and 0.76 to 1.26 eV for Poole–Frenkel emission were estimated at the hetero-interface. To better understand the conduction mechanism between the hetero-interface and temperature-dependent J–V, a calibrated TCAD simulation was carried out.

The CO gas sensing characteristics of polar GaN (P-GaN) and non-polar GaN (NP-GaN) thin-films grown by RF-plasma assisted molecular beam epitaxy on c-Al2O3 and r-Al2O3 substrate is analyzed. The temperature-dependent (27-300 degrees C) current-voltage (I-V) measurements were performed for both (P-GaN & NP-GaN) Schottky barrier diodes having identical device dimensions with Au as the metal contact. The Schottky barrier height increases with the increment in temperature, while vice versa was perceived for the ideality factor and series resistance. The I-V characteristics dictated that the terminal current for P-GaN is 25 times that of NP-GaN, further corroborated by simulation results. The I-V curve fitting suggests the initial emission of charge carrier from a trapped state to a continuum of electronic state, following the Frenkel-Poole emission model for P-GaN. The NP-GaN demonstrated a higher surface-to-volume ratio and native (shallow and deep level) defects corresponding to V-Ga and O-N as compared to the P-GaN. The sensing response obtained for the NP-GaN for 100 ppm CO gas at 300 degrees C is similar to 33%, which is about seven times the response in the case of P-GaN. The role of native defects and the potentiality of the fabricated NP-GaN over P-GaN films in providing a better sensing characteristic by reducing the current conduction paths are elaborated. (C) 2021 Elsevier B.V. All rights reserved.

The sensing properties of GaN and hydrothermal synthesized transition metal di-selenides nanostructure decorated WSe2/GaN and MoSe2/GaN hybrid structures are reported for 100 ppm CO gas for temperature range of 27 degrees C-250 degrees C. The fabricated devices divulged that Schottky Barrier Height increases from 0.6 eV to 1.2 eV with increment in temperature while vice versa was perceived for series resistance, except for MoSe2/GaN structure. The gas sensing measurements revealed that the threshold temperature for CO sensing for GaN, WSe2/GaN and MoSe2/GaN based sensors was 100 degrees C, 100 degrees Cand 150 degrees C along with a peak response value of 23.3 %, 38.8 % and 43.1 %, respectively. The gas sensing data displayed a highly competitive response & recovery time as all the fabricated devices were able to detect CO within 78 s of exposure. The recovery time of the devices varied in a similar fashion, demonstrating the promising potential of W(Mo)Se-2/GaN hybrid structures for efficient CO gas detection.

In this work, a high-performance room temperature NO2 chemoresistive gas sensor is fabricated using a MoS2/ZnO nanohybrid. The nanohybrid is synthesized by drop-casting liquid exfoliated MoS2 nanosheets on ZnO nanorods. The uniform network-like distribution of MoS2 nanosheets on the nanorods is confirmed by various characterization techniques. Under UV-activation, the nanohybrid sensor exhibits remarkable responses of 91% and 2310% at 5 and 500 ppb NO2, respectively. In addition, full recovery to the base resistance is observed in each sensing cycle. The low concentration sensitivity is 0.135 ppb(-1) and the lowest detection limit is estimated to be around 0.2 ppb. These two values are superior when compared with other reports. The adsorption/desorption kinetics has been studied in detail using the Langmuir adsorption model. The saturated response, the adsorption, and the desorption constant are determined to be 2744%, 3.52 x 10-5 ppb(-1) s(-1), and 3.50 x 10(-3) s(-1), respectively. The outstanding performance of the sensor can be attributed to the synergetic effects of MoS2 and ZnO including creation of abundant adsorption sites and fast charge carrier migration.

Internet of Things (IoT) is increasingly set to be used and implemented in every sphere of technology where low-cost sensors, whose sensing needs are not so rigorous, are required for massive cost reduction. This article reports the fabrication of low-cost ZnO Nanoparticles incorporated Polydimethylsiloxane (PDMS)/Porous PDMS stack capacitive pressure sensor, which can be used for low, as well as high-stress monitoring applications. High-performance electrical and mechanical properties have been discerned with the proposed device structure. For a comparative study with conventional geometry, a porous PDMS sensor is also fabricated and characterized. The proposed sensor exhibits non-saturation behaviour even beyond 250 mmHg of the applied load. It also demonstrated the highest failure stress at 2.34 kgf/mm(2), which could serve as an improvised replacement for other polymer layers under high-stress conditions. The sensitivity of the sensor is found to be 0.38 pF/cm(2) mmHg at 12 mmHg applied pressure. The performance of the sensor, connecting to an embedded setup prototype involving microcontroller and other electrical components, was also demonstrated by placing objects in incremental order. These values give the proposed sensor high potential as fulfilling one of the vital requirement criteria in the IoT industry.

The use of expensive catalysts (e.g. platinum) and high operation temperature ( > 300 degrees C) has plagued the cost-effectiveness and thereby the commercialization of III-Nitride semiconductors based gas sensing technology. Inadequate research on the development of catalyst-free room-temperature CO sensing using GaN based structures is the critical reason behind the subjugation of this area. Therefore, in the present article, we aimed the development of GaN & AlGaN/GaN heterostructure based gas sensors for catalyst-free low-temperature CO sensing (at 100 ppm). To explore the underlying science behind such mechanism, the morphological, electronic and electrical properties of the devices were thoroughly investigated. The analysis revealed that CO sensing on GaN (and AlGaN/GaN heterostructure) is governed via the chemical nature of ambient-oxidation induced amorphous oxide layer (O-2(-), O2- or OH(- )species), which acts as donor/acceptor state at the surface. Besides, the critical device parameters like Schottky barrier height and electron accumulation associated with series resistance and leakage current (forward/reverse) displayed significant variation with temperature (27-250 degrees C) and perturbed the effective carrier transport/collection and ultimately the device efficiency. The study demonstrates that nanostructured surfaces can open avenues for the development of catalyst-free room temperature operating III-Nitride semiconductor based CO sensors.

Gallium Nitride (GaN) and Zinc Oxide (ZnO) are well established semiconductors with their heterostructures opening avenues for the future of next generation sensing and opto-electronics technologies due to their low lattice mismatch and high exciton energy. ZnO/GaN heterostructure based ultraviolet photodetectors with complimentary material properties are expected to yield optimum efficiency, though their performance has remained low due to challenges related to interfacial properties. Inadequate analysis of ZnO/GaN interfacial properties/states viz. electronic structure, band offsets, localized charge density and defect states associated with overlayer (i.e. ZnO) thickness, and their influence on device performance has remained as an underestimated issue. Interestingly, literature reports a huge anomaly in the valence band offset (VBO) at ZnO/GaN interfaces, which being an effective measure of charge transport assist in the optimization of photodetector efficiency. Therefore, in the present report, we have fabricated ZnO/GaN heterostructure (with variable ZnO thickness) based Schottky barrier photodectors and investigated the dependence of photosensitivity & other device parameters on interfacial states/properties. We have witnessed a peak responsivity & detectivity of 225 mA/W-1 & 4.83 (x10(13)) Jones and a high speed photoswitching associated with the band offset, barrier height & defect states at the ZnO/GaN heterojunction. The underlying scientific phenomenon (e.g. interfacial dipole strength, charge accumulation etc.) leading to perturbations & discontinuities in interfacial/electronic states were also correlated and discussed in detail.

We employed simple shear-force-dominated planetary ball milling to prepare graphene on a large scale (200 g per cycle) with less structural defects.