Micro and Nanostructures最新文献

A novel sustainable approach for enhancing the efficiency of dye-sensitized solar cells (DSSCs) involves the utilization of a combination of ZnO and carbon dots (CDs) derived from Citrus medica fruit extract, along with microwave-synthesized TiO₂ nanoparticles for the preparation of the photoanode. Natural dyes such as Hibiscus rosa-sinensis and Allium Cepa peel are employed as sensitizers to reduce production costs. This co-activation method has demonstrated a significant improvement in the output parameters of the devices. Notably, the photoanode co-activated with ZnO-CD composite (ZnO-CD/TiO₂) exhibits the most favorable output parameters when combined with Hibiscus rosa-sinensis dye (open circuit voltage (Voc) = 0.80 V, short circuit current density (Jsc) = 6.62 mA/cm², fill factor (FF) = 64.20 %, photo conversion efficiency (PCE) = 3.40 %) and Allium Cepa peel dye (Voc = 0.81 V, Jsc = 6.79 mA/cm², FF = 65.70 %, PCE = 3.61 %). When paired with Allium Cepa dye, the CD modified photoanode (CD/TiO₂) offers Voc = 0.73 V, Jsc = 6.64 mA/cm², FF = 61.27 % and PCE = 2.97 %. Similarly, when combined with Hibiscus rosa-sinensis dye, the output parameters of the CD/TiO₂ photoanode are Voc = 0.72 V, Jsc = 6.54 mA/cm², FF = 64.4 % and PCE = 3.03 %. In comparison to all tested devices, the unmodified photoanode (TiO₂) displayed the lowest performance, with parameters such as Voc = 0.59 V, Jsc = 6.45 mA/cm², FF = 52.5 %, PCE = 2.10 % using Allium Cepa peel dye, and Voc = 0.66 V, Jsc = 6 mA/cm², FF = 51.60 %, PCE = 2.04 % using Hibiscus rosa-sinensis dye. Furthermore, the co-activation process has been shown to enhance the stability of the devices. While the unmodified photoanodes ceased to operate after eight days, the ZnO-CD composite co-activated photoanodes retained their initial efficiencies up to 61.50 % and 68.53 % with the Allium Cepa peel dye and Hibiscus rosa-sinensis dye, respectively. Therefore, this study underscores the potential of the synthesized composite material in enhancing the performance of natural DSSCs.

In this paper, a 4H–SiC Schottky barrier field-effect transistor with a P⁺ doping Pocket based on dielectric modulation effect for label-free detection of biomolecules has been proposed. Upon optimization of the length and position of P⁺ doping pocket, the sensitivity of the biosensor achieves the maximum when it is located within the channel 1 nm away from the Schottky contact with a length of 5 nm. Simulations have been performed for different dielectric constants and biomolecules with different charge densities by Sentaurus TCAD. The results show that the new structure has an on-current sensitivity of 1.03 × 10⁸, a maximum transconductance sensitivity of 6.24 × 10⁷, a threshold voltage sensitivity of 65 mV, and an I_on/I_off ratio sensitivity of 1.8 × 10⁴ for neutral biomolecules with K = 12. In addition, the fill factor of the cavity and linearity of the proposed structure are considered in this paper. Further, the on-current sensitivity of our proposed structure is gauged against state of the art, which demonstrate a high sensitivity of our proposed biosensors. The smaller size and prominent sensitivity characteristics of the biosensor proposed in this paper have made it widely used in the field of biomedical detection that requires high integration and efficient detection.

This work introduces an innovative Source-All-Around Vertical Tunnel Field-Effect Transistor (SAA-VTFET) design based on III-V semiconductors. The unique combination of a GaSb/InSb heterojunction, a wider tunneling space, and an n⁺ source pocket significantly enhances band-to-band tunneling (BTBT), leading to exceptional on-current levels. The device architecture utilizes InSb in the source pocket and channel, materials chosen for their properties that enable efficient carrier transport, ultimately boosting overall device performance. Through meticulous optimization, the SAA-VTFET achieves an I₆₀ (I_ds at SS = 60mV/dec) of 2.73 × 10⁻⁴ A/μm, an exceptionally low off-current of 1.7 × 10⁻¹⁷ A/μm, a low threshold voltage of 0.16 V, an outstanding I_ON/I_OFF Ratio of 1.64 × 10¹³, and an attractive subthreshold swing (point SS of 4 mV/dec, average SS of 7 mV/dec). These remarkable achievements underscore the SAA-VTFET's potential to surpass conventional TFETs, paving the way for advanced low-power, high-speed electronics.

This paper presents a simulation study on a 12 nm Gate-all-around n-type Metal Oxide Semiconductor (GAA-nMOSFET), investigating the effects of temperature variations and doping concentrations. The structure of the device has three fins, and the channel is surrounded by gate material to reduce the short channel effect (SCE) and electrostatic capacitance. Various parameters such as threshold voltage (V_th), I_on/I_off ratio, drain-induced barrier lowering (DIBL), and sub-threshold swing (SS) are evaluated at different temperatures 250 K, 300 K, and 350 K, doping concentrations of 10¹⁶cm⁻³, 10¹⁷cm⁻³, and 10¹⁸cm⁻³, with a high voltage of 0.65V. At a temperature of 250 K, in comparison to the 10¹⁶cm⁻³ doping concentration attention, the V_th is observed to be 0.31V, while the I_on/I_off ratio is measured at 0.33e⁻¹⁴. Moreover, the DIBL experiences a reduction of 25 %, whereas the SS increases by 76 %. Furthermore, when the temperature is raised to 300 K relative to the 10¹⁷cm⁻³ doping concentration, the V_th increases to 0.32 V, and the I_on/I_off current ratio rises to 0.45e⁻¹⁴. Meanwhile, the DIBL experiences a decrease of 20 %, and the SS increases by 71 %. Finally, at a temperature of 350 K concerning 10¹⁸cm⁻³ doping concentration, the V_th is measured at 0.34 V, and the I_on/I_off current ratio reaches 0.47e⁻¹⁴ Concurrently, the DIBL shows a decrease of 28 %, While the SS increases to 79 %. To reduce electrostatic capacitance and leakage current, the use of a high-k dielectric material in a GAA-nMOSFET device is investigated. Improved performance traits such as decreased SCE, low DIBL, and strong SS are displayed. Additionally, the connection between threshold voltage and doping concentration is investigated. The effect of temperature variations and doping concentration on many essential characteristics of 12 nm GAA-nMOSFET shows the potential benefits of the device's unique architecture and material. The conclusions are supported through circuit schematics, simulations, and experimental data in this article.

Molecular dynamics simulations were performed to investigate a novel technique for cutting gallium nitride (GaN) with the help of graphene lubrication. A scratch model of GaN coated with graphene was developed, and changes in the surface topography, atomic displacement, atomic cutting force, temperature, defect atoms, and the process of graphene fracture. The graphene coating on the surface of the GaN workpiece inhibits the movement of atoms in the workpiece during the scratching process, with minimal chip deposition in front of the abrasive. The amount of defective atoms rises as the depth of the scratch increases. Graphene is more susceptible to fracture at larger depths. In addition, using graphene lubrication to cut GaN can enhance surface integrity while concurrently diminishing material removal effectiveness. Furthermore, using graphene as a solid lubricant on various materials, can also greatly reduce friction. These findings provide insights for the design and processing of these brittle materials.

Oil pollution poses a major threat to both human health and economic development, and therefore the development and improvement of oil-water separation technology is urgent. Traditional methods have problems such as complicated preparation, high cost and the vulnerability of lipophilic materials to oil contamination. Therefore, finding an inorganic material that meets the requirements of underwater superoleophobic performance and reduces surface modification has become a new demand. In this study, natural pumice was found for the first time to have excellent underwater superoleophobic performance and chemical stability, and the underwater superoleophobic filter membrane was prepared by vacuum adsorption using hydrogen bond cross-linking between natural pumice and PVA. The experimental data show that the prepared PVA/natural pumice ultrafiltration membrane has superhydrophilic and superoleophobic properties, and exhibits excellent stability (OWA>150°) under the harsh environment of strong acid and strong alkali. In addition, the composite membrane has good emulsion separation efficiency (>97 %) and a separation flux of 39.91 Lm^-2h^-1. It is demonstrated that the composite membrane has oleophobic and wettable properties, and is capable of separating both oil-water mixtures without phase mixing and oil-in-water emulsions without oil contamination. This study provides a new idea for the preparation of superoleophobic materials for oil-water separation, which has the potential for large-scale application.

Al-doped ZnO (AZO) thin films with different layers were prepared by sol-gel method. The SEM, XRD and AFM for three layers thin films demonstrates high crystal quality and low roughness. ZnO nanorods arrays (NRs) with different AZO seed layers were fabricated using hydrothermal process, and the effect of AZO seed layers on the structural, optical, and electrical characteristics was investigated. When there are three AZO seed layers present, ZnO NRs exhibit fewer surface states, smaller interface charge transfer resistance (R_ce = 6.1 × 10³Ωand R_ct = 6.6 × 10⁶Ω), longer carrier lifetimes (${\tau }_e$ = 4.0 ms), higher carrier concentration (N_D = 4.73 × 10¹⁹ cm⁻³), and narrower depletion region width W = 3.1 nm. Under weak UV light 381 nm (5.68 mW/cm²) at a bias −0.5 V, Ag/ZnO NRs Schottky devices with three AZO seed layers display a comparatively strong responsivity 34.64 mA/W. Appropriate AZO seed layers are favorable for highly efficient ZnO NRs-based photoelectric conversion devices.

In order to solve the electrical performance limitations of horizontal multilayer graphene nanoribbon (H-MLGNR) based interconnect, a new geometric structure of vertical multilayer graphene nanoribbon (V-MLGNR) based interconnect is proposed in this paper. A numerical model for H-MLGNR and V-MLGNR based interconnects is established to investigate the performance in time and frequency domain, where the high-k dielectric materials (HKDM) are introduced for improving their transmission performance. The computation results demonstrate that the delay time for H-MLGNR and V-MLGNR based interconnects with embedded BaTiO₃–Ni case can be reduced over 89.601 % and 93.723 % in comparison to the original H-MLGNR and V-MLGNR based interconnects, respectively. The corresponding 3-dB bandwidth for them can be expanded over 1.928 and 2.957 times, respectively. Moreover, it is manifested that the delay time of V-MLGNR based interconnect for the original, embedding the HfO₂, TiO₂, SrTiO₃, BaTiO₃, 6.0 vol% BaTiO₃–Ni and 12.0 vol% BaTiO₃–Ni cases can be reduced over 11.644 %, 13.269 %, 16.851 %, 22.311 %, 27.589 %, 33.608 % and 46.556 % as compared with the conventional H-MLGNR based interconnect, respectively. Meanwhile the corresponding 3-dB bandwidth of the former for the original, embedding the HfO₂, TiO₂, SrTiO₃, BaTiO₃, 6.0 vol% BaTiO₃–Ni and 12.0 vol% BaTiO₃–Ni cases can be enhanced over 1.113, 1.126, 1.155, 1.207, 1.266, 1.366 and 1.737 times as compared with the latter, respectively. In addition, the signal integrity of the proposed V-MLGNR based interconnects with embedded HKDM is greater than H-MLGNR based interconnects, while the power consumption of the former is slightly higher than the latter. Therefore, the proposed new interconnect structure concerning the V-MLGNR with embedded HKDM would be rewarding to enhance transmission performance of interconnect system in VLIS circuits.

For the first time, we reported the noise and sensitivity analysis of the Dielectric Modulated Reconfigurable Silicon Nanowire-based Schottky Barrier Transistor (DMR SiNW-SBT) for biosensor applications. To validate the simulation, we present experimental calibration of the DMR SiNW-SBT biosensor. The biomolecules having different dielectric constants and charge densities are immobilized in the cavity region under the control gate. These biomolecules modulate the Schottky junction width at the source channel interface and enhance the drain current of the biosensor. The simulation results indicate that the proposed device I_ON and V_TH sensitivity improved by 54.65 % and 85.71 %, respectively, with the state-of-the-art biosensors. Noise analysis shows that the NF_min decreased by 190.32 % and offers a low source impedance of 70Ω, which minimizes signal loss and distortion. Additionally, we investigate the linearity parameters that outperformed the FET-based biosensors. The gm3 experiences a reduction of 123.21 %, while the VIP3 sees an increase of 7.87 % and the IIP3 shows a rise of 7.21 %. Furthermore, we have conducted device optimization by varying the cavity length and thickness. We also outline potential fabrication steps for the DMR SiNW-SBT biosensor. Thus, results show that the proposed biosensor emerges as a promising candidate for advanced biosensing applications with high sensitivity, enhanced linearity, and robust noise resilience.