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In the current work, n-type Y-doped ZnO nanowires (n-Y:ZnO) and p-type Si heterojunctions are fabricated by employing two-step chemical bath deposition (CBD) process. The work demonstrates the systematic incorporation of Y in ZnO nanowires for achieving the low power UV response. The crystalline nature, morphology, chemical compositions of doped nanowires are studied extensively by employing XRD, FESEM, HRTEM, elemental mapping, EDS and XPS. The change in defect states due to Y incorporation has been studied in detail by using deconvoluated PL spectra. The results indicate that ZnO nanowires exhibit Zn interstitials dependent huge UV/blue luminescence and oxygen vacancy related lowest green luminescence simultaneously for selective 1% Y-doping. The best self-powered photoresponse has been achieved for 1% Y-doped ZnO nanowires/p-Si heterojunction under relatively low power UV illumination (374 nm @5 mW/cm2). More significantly, at self-powered mode, such heterojunction has been delivered a stable and fast (<1 s) photoresponse with a maximum responsivity of 225 mA/W and high On/Off ratio of ∼104. The work provides an insight into the fabrication of heterojunction UV detectors for next-generation self-powered, large area optoelectronic devices. • Growth of Y:ZnO nanowires on Si substrate by using in-situ rare earth (Y) doping in CBD method. • Physical, chemical, optical and electrical characterizations of such heterojunctions for optoelectronic applications. • Simultaneous generation of Zn interstitials and reduction of O vacancies play a crucial role for reducing the dark current. • Y:ZnO nanowires/Si heterojunctions exhibit relatively higher responsivity and superior response time in self-powered mode. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nickel nanoparticles (Ni Nps) synthesized using hydroxypropylmethylcellulose (HPMC). [•] HPMC stabilized Ni Nps form nanoflowers like structure with chain configuration. [•] The synthesized nickel nanoparticles are ferromagnetic. [•] Magnetic properties of HPMC stabilized Ni Nps are quite different from bared Ni Nps. [•] The resulting Ni Nps are active and recyclable catalyst for Suzuki coupling reactions. [ABSTRACT FROM AUTHOR]

This paper presents a new semianalytical model for the energy dispersion of the holes in the inversion layer of pMOS transistors. The wave vector dependence of the energy inside the 2-D subbands is described with an analytical, nonparabolic, and anisotropic expression. The procedure to extract the parameters of the model is transparent and simple, and we have used the band structure obtained with the k ·p method to calibrate the model for silicon MOSFETs with different crystal orientations. The model is validated by calculating several transport-related quantities in the inversion layer of a heavily doped pMOSFET and by systematically comparing the results to the corresponding k · p calculations. Finally, we have used the newly developed band-structure model to calculate the effective mobility of pMOS transistors and compare the results with the experimental data. The overall computational complexity of our model is dramatically smaller compared to a fully numerical treatment (such as the k · p method); hence, our approach opens new possibilities for the physically based modeling of pMOS transistors. [ABSTRACT FROM AUTHOR]

Abstract: The benefit of high performance strained Si CMOS in terms of technology generations is quantified. It is shown that a 0.3 μm gate length strained Si/Si0.75Ge0.25 CMOS technology has the same gate delay as conventional technology having an effective gate length of 0.14 μm, but without the cost of re-tooling. Transconductance enhancements over conventional CMOS in excess of 200% are demonstrated for surface channel n- and p-MOSFETs using a Si0.75Ge0.25 virtual substrate without CMP and a high thermal budget process. To our knowledge these represent the best results reported to date at these dimensions. [Copyright &y& Elsevier]

Performance enhancements of up to 170% in drain current, maximum transconductance, and field-effect mobility are presented for nMOSFETs fabricated with strained-Si channels compared with identically processed bulk Si MOSFETs. A novel layer structure comprising Si/Si[sub 0.7]Ge[sub 0.3] on an Si[sub 0.85]Ge[sub 0.15] virtual substrate (VS) offers improved performance advantages and a strain-compensated structure. A high thermal budget process produces devices having excellent on/off-state drain-current characteristics, transconductance, and subthreshold characteristics. The virtual substrate does not require chemical-mechanical polishing and the same performance enhancement is achieved with and without a titanium salicide process. [ABSTRACT FROM AUTHOR]

• Experimental observation of emission lines originated from band-splitting phenomenon in InP nanotubes. • Growth of InP nanotubes by MOCVD on patterned template developed by e-beam lithography. • Developing a theoretical framework for investigating the band splitting effect in semiconductor nanotubes. Two spectral emission lines originated from band splitting in Indium Phosphide nanotubes are observed experimentally. The nanotubes are grown by Metal-Organic Chemical Vapour Deposition on patterned template developed by electron beam lithography. The splitting effect arising from spatial confinement-induced momentum quantization on the band structure of nanotubes is investigated by developing a theoretical model. The incorporation of momentum quantization in sp3s*-model with spin-orbit coupling indicates the splitting of Γ-point into two different symmetric points, which emit two spectral lines as confirmed by cathodoluminescence spectra. The observation provides novel insight into the band structure based transport behaviour of semiconductor quantum devices. [ABSTRACT FROM AUTHOR]

In the current work, n-ZnO nanowires are grown by employing double-step chemical bath deposition (CBD) technique on p-Si substrate for the fabrication of n-ZnO nanowires/p-Si heterojunction diodes. The as-deposited ZnO seed layer is furnace annealed at 400 °C and 600 °C for 30 min in argon ambient for studying comparative changes of their optoelectronic properties. The systematic change of surface morphology, chemical compositions, crystallite structure, oxidation states, defect levels and photodetecting properties due to annealing of the seed layer has been investigated. Annealing the seed layer at 400 °C exhibits a nanosphere-like structure and provides superior nucleation sites for vertical growth of the nanowires in comparison to the as-deposited and 600 °C -annealed samples. The electrical, electro-optical and physical characterization results suggest the nanowires grown on 400 °C -annealed ZnO seeds to provide superior performance. [ABSTRACT FROM AUTHOR]

The current article demonstrates a novel diagrammatic approach for the detection and quantification of polar and non-polar/ionic adulterants in milk by employing electrical impedance spectroscopy (EIS). For such study, some commonly used milk adulterants including melamine, starch, urea, allantoin, cyanuric acid, benzoic acid, ammonium sulphate and sodium bicarbonate are incorporated in a controlled manner in the pure milk sample. The presence of such adulterants in milk is confirmed by Fourier transform mid-infrared (FT-MIR) spectroscopy prior to impedimetric measurements. A Pt/Teflon/SiO2/Si biosensor device is fabricated for EIS measurement where the combination of SiO2 and Teflon layer thicknesses are optimized to obtain an appropriate hydrophobicity/dielectricity for the liquid milk samples. The EIS study shows an opposite trend in the variation of electrical impedance, capacitance and conductance for the polar samples in comparison to non-polar/ionic adulterants, upon their controlled addition from 0.5 to 9 (mg/g). Such results are utilized for detection and quantification of the milk-adulterants by developing a diagrammatic approach based on impedimetric phase angle-modulus mapping. Such diagrammatic impedance spectroscopy provides a generic scheme for a rapid, cost-effective and point-of-care detection and quantification of adulterants in milk which can be further extended to other bio-consumables. • EIS detection scheme to identify polar and non-polar/ionic adulterants in milk. • Pt/teflon/SiO2/Si biosensor device fabricated for EIS measurement of liquid sample. • The device can detect milk adulterant concentration ranging from 0.05 to 0.9% (w/w). • Impedimetric phase angle-modulus diagram can map various adulterants in milk. [ABSTRACT FROM AUTHOR]

• Growth of CuO film and ZnO nanowires by employing CBD method. • Potential of ZnO nanowires for improving power conversion efficiency. • Improvement of photovoltaic parametrices of p-CuO/n-ZnO NWs heterojunction. • Achievement of a significantly high solar energy conversion efficiency of 4.19%. P-type cupric oxide (p-CuO) and p-type cupric-oxide/n-type zinc oxide nanowires (p-CuO/n-ZnO NWs) heterojunction diodes were fabricated by employing chemical bath deposition technique on n-silicon (n-Si) substrate. The work demonstrates the potential of zinc oxide nanowires as window layer owing to its wide and direct band gap for metal oxide based solar cells. Optical and electronic properties of the CuO film and ZnO nanowires including refractive index, absorption coefficient and band gaps were investigated by using spectroscopic ellipsometric analysis. Impact of nanowire morphology, chemical composition and crystallite structures on optical and photovoltaic performance of p-CuO/n-Si and p-CuO/n-ZnO NWs were investigated. Absorption coefficient in the near UV–visible range was observed to improve significantly by incorporating n-ZnO nanowires which was desired for the solar cell applications. The comparative photovoltaic performance showed improvements of both the short-circuit current density (J sc) and open circuit voltage (V oc), due to reduced interface recombination and enhanced absorption for the increased surface-to-volume ratio of ZnO nanowires in the p-CuO/n-ZnO NWs heterojunction. Photovoltaic performance with J sc , V oc and power conversion efficiency of 11.1 mA/cm2, 1.1 V and 4.19% was obtained. Therefore, the work emphasizes importance of using the combination of n-ZnO nanowires and p-CuO film as the wide- and low- band gap materials for improving performance of the future low-cost solar cell with superior efficiency. [ABSTRACT FROM AUTHOR]

• Surfactant assisted in situ synthesis of silver nanoparticle deposited rodlike PPY. • Rodlike PPY-Ag nanocomposite has exhibited excellent sensitivity values of 8.22 mAμM−1 for detection of dopamine. • Rodlike PPY-Ag nanocomposite shows detection limit of 0.00005 μM. • Biocompatibility assay of the rodlike PPY-Ag nanocomposite has exhibited less toxic nature to mouse fibroblast cell. • Antimicrobial nature of the synthesized rodlike PPY-Ag nanocomposite has also been observed towards E.coli and S. aureus. Conducting polymer-noble metal nanocomposites have attracted considerable interest as electrochemical sensors because they provide better sensing responses to different analytes. We report the synthesis of rod like polypyrrole (PPY)-Ag nanocomposite using sodium cholate as soft-template for sensing nanomolar concentration of dopamine (DA). The nanocomposites were characterized by employing FT-IR, XRD, scanning and transmission electron microscopic analysis. Electrochemical impedance spectroscopy and cyclic voltammetry experiments were performed for electrochemical characterization of the PPY-Ag nanocomposite deposited on glassy carbon electrode (GCE). Electrochemical detection of DA using this nanocomposite deposited on GCE was done following linear sweep voltammetry. The PPY-Ag nanocomposite deposited electrode showed improved sensitivity value of 8.22 mAμM−1 for DA and a detection limit of 0.00005 μM. Biocompatibility assay of the developed PPY-Ag nanocomposites have exhibited less toxicity to mouse fibroblast cell even in comparison to that of PPY without silver. Antimicrobial property of the PPY-Ag nanocomposites towards E.coli and S. Aureus have also been observed. [ABSTRACT FROM AUTHOR]

In the current work, a single crystalline β-Gallium Oxide (Ga 2 O 3) thin film (~15 nm) is grown on Si-substrate by employing catalyst-modified vapor-liquid-solid (VLS) method. The FESEM and AFM images indicate the formation of a continuous film with small surface roughness. XRD measurement confirms the formation of a highly crystalline < 1 ¯ 11 >-plane of β-phase of Ga 2 O 3. The chemical states and optical properties of such films are analyzed by X-ray photoelectron spectroscopy (XPS) and Spectroscopic ellipsometry (SE). The energy bandgap, refractive index and extinction coefficient of the grown β-Ga 2 O 3 film are obtained to be 4.78 eV, 1.84 and 0.10, respectively. The vacancies/defect states are studied from Photoluminescence (PL) spectra where the major PL-peaks corroborate with the transitional energy values obtained from SE measurement. Therefore, the study suggests that the VLS method, amongst the state-of-the-art growth techniques, is capable of growing high-quality single crystalline β-Ga 2 O 3 thin film in a relatively simple and cost-effective approach. Image 1061 • Growth of β-Ga 2 O 3 film is reported, for the first time, by employing VLS technique. • The Au catalyst is modified to provide ambient condition for rapid growth of the film. • Single crystalline film (~15 nm) is achieved by adopting such catalyst modified method. [ABSTRACT FROM AUTHOR]

In general, defects are crucial in designing the different properties of two-dimensional materials. Therefore large variations in the electric and optical characteristics of two-dimensional layered molybdenum disulphide might be attributed to defects. This study presents the design of a temperature and nitrogen sensor based on few-layer molybdenum disulfide sheets (FLMS), which was developed from bulk MoS 2 (BMS) through an exfoliation approach. The produced sulfur defect, molybdenum defect, line defect, and plane defect were characterized by scanning transmission electron microscopy (STEM), which substantially impacts the sensing characteristics of the resulting FLMS. Our theoretical analysis validates that the sulfur vacancies of the MoS 2 lattice improve sensing performance by promoting effective charge transfer and surface interactions with target analytes. The FLMS-based sensor showed a high sensitivity for detecting nitrogen gas with a detection limit (LOD) of ~ 0.18 ppm. Additionally, temperature-detecting capabilities were assessed over various temperatures, showing outstanding stability and repeatability. To the best of our knowledge, this material is the first of its kind, demonstrating visible N 2 gas sensing with chromic behaviour., (© 2024. The Author(s).)

This study devised a label-free electrochemical immunosensor for the quantitative detection of alpha-fetoprotein (AFP). 3-Polythiophene acetic acid (3-PTAA) nanoparticles were anchored onto a few-layer graphene (FLG) nanosheet, and the resulting nanocomposite was utilized as the immunosensor platform. The AFP antibody (anti-AFP) was immobilized on 3-PTAA@FLG via a covalent interaction between the amine group of anti-AFP and the carboxylic group of 3-PTAA via ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/ N -hydroxysuccinimide (NHS) coupling. FLG is largely responsible for providing electrochemical signals, whereas 3-PTAA nanoparticles are well-known for their ability to be compatible with biological molecules in neutral aqueous solutions. Moreover, the carboxyl group present in 3-PTAA effectively binds anti-AFP through EDC/NHS conjugation. Owing to good dispersibility and higher surface area of 3-PTAA, it is very convenient for casting the polymer directly on the electrode substrate followed by immobilization of anti-AFP. Thus, it is feasible to regulate the activity of AFP proteins and control the spatial distribution of the immobilized anti-AFP proteins. The electrochemical sensing performance was assessed via cyclic voltammetry and electrochemical impedance spectroscopy. For an increase in the bioconjugate concentration, the results demonstrated a surge in charge-transfer resistance and a consequent decline in the current response. This approach effectively detected AFP at an extended dynamic range of 0.0001-250 ng/mL with a detection limit of 0.047 pg/mL. Furthermore, the sensing capacity of the immunosensor for AFP detection has been demonstrated to be steady in real human serum cultures. Our approach exhibits good electrochemical performance in terms of reproducibility, selectivity, and stability, which would surely impart budding applications in the clinical diagnosis of several other tumor markers.

A green, efficient synthesis of cadmium oxide decorated reduced graphene oxide nanocomposites (RGO/CdO) was prepared by one-step co-precipitation and hydrothermal method. Crystalline nature of the nanocomposites was characterized by X-ray diffraction analysis. To evaluate the structural morphology and particle size, high resolution transmission electron microscopy were used. X-ray photoelectron spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy techniques were employed to establish chemical structure of the nanocomposites and Atomic Force Microscopy was done to measure the thickness. The optical properties were evaluated by UV-visible absorption spectroscopy. Thermo-gravimetric analysis, BET surface area and zeta potential measurements were carried out to study the thermal and surface characteristics. The CdO nano-particles (NPs) decorated on RGO sheets exhibit better electrical conductivity compared to RGO. The antibacterial activity of the nanocomposites has also been monitored in different culture media imparting good potentiality than RGO., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Electrical and physical properties of a metal-oxide-semiconductor [MOS] structure using atomic layer-deposited high-k dielectrics (TiO2/Al2O3) and epitaxial GaAs [epi-GaAs] grown on Ge(100) substrates have been investigated. The epi-GaAs, either undoped or Zn-doped, was grown using metal-organic chemical vapor deposition method at 620°C to 650°C. The diffusion of Ge atoms into epi-GaAs resulted in auto-doping, and therefore, an n-MOS behavior was observed for undoped and Zn-doped epi-GaAs with the doping concentration up to approximately 1017 cm-3. This is attributed to the diffusion of a significant amount of Ge atoms from the Ge substrate as confirmed by the simulation using SILVACO software and also from the secondary ion mass spectrometry analyses. The Zn-doped epi-GaAs with a doping concentration of approximately 1018 cm-3 converts the epi-GaAs layer into p-type since the Zn doping is relatively higher than the out-diffused Ge concentration. The capacitance-voltage characteristics show similar frequency dispersion and leakage current for n-type and p-type epi-GaAs layers with very low hysteresis voltage (approximately 10 mV).PACS: 81.15.Gh.