Micro and Nanostructures最新文献

A frequency-domain model is developed to analyze isolated interconnects of multilayer graphene-nanoribbon (MLGNR) and mixed carbon-nanotube bundle (MCB) driven by CMOS gates. The model derived is founded on an equivalent-single-conductor model of MLGNR and MCB that takes thermal considerations into account (i.e. TD-ESC). The model includes the derivation of transfer function of interconnect to estimate its delay and bandwidth performance. The attained results, reveals that among the neutral MLGNR (N-MLGNR), intercalation doped MLGNR (ID-MLGNR) intercalated with FeCl₃, MCB and Cu interconnects, FeCl₃ ID-MLGNR achieves the best bandwidth efficiency. At a global interconnect length of 1 mm, FeCl₃ ID-MLGNR outperforms N-MLGNR, MCB, and Cu in terms of bandwidth with an improved bandwidth value of 12.2 GHz, 7 GHz, and 61.4 GHz, respectively. Further, employing the proposed CMOS-gate-driven model, for FeCl₃ ID-MLGNR, bandwidth is improved by nearly 7.52 × at global length (∼1 mm) in relation to the linear resistance model. Additionally, TD-ESC dependency of the proposed model reveals that FeCl₃ ID-MLGNR becomes more stable as interconnect resistance increases.

In this paper, an enhancement-mode (E-mode) NiO/β-Ga₂O₃ heterojunction field-effect transistor (HJ-FET) with high conduction band offset (ΔE_C) and thin recessed channel is proposed and studied by Sentaurus TCAD. Different from the existing HJ-FET with low ΔE_C alignment, the High ΔE_C HJ-FET can achieve a much lower on-resistance (R_on) due to the strong electron confinement effect. More importantly, the disadvantage in the threshold voltage (V_th) is compensated by reducing the thickness of the recessed channel, maintaining an almost unchanged R_on with the help of the special surface conduction channel. Compared with the corresponding Low ΔE_C HJ-FET, at the same V_th ($\sim$ 0.82 V), the R_on is decreased from 135 Ω/mm to 90.7 Ω/mm and the maximum drain current is increased from 14.9 mA/mm to 83.1 mA/mm. By adding a top p-NiO layer for further optimization, a greatly improved power figure of merit (P-FOM) of 2.29 GW/cm² is achieved among the E-mode HJ-FETs. These results show that the proposed High ΔE_C HJ-FET with thin recessed channel is probably a better choice to achieve the high-performance E-mode lateral HJ-FET.

In this paper, a Schottky barrier field effect transistor biosensor with dual-source, dual-drain, and a suspended beam channel (DSDD-SB-FET) is proposed and its biosensor performance is investigated by simulation. The simulation results show that compared with the conventional 6H–SiC Schottky barrier field effect transistor (6H-SiC-SB-FET) biosensor, the new structure proposed in this paper has superior sensitivity characteristics. The S_Ion is 1.83 × 10⁸, S_gm,max is 1.44 × 10⁸, S_Ion/Ioff is 1.53 × 10⁷, and S_SS is 83 % at K = 12, which are respectively 554 times, 476 times, 2.76 × 10⁴ times, and 61 % higher than those of the 6H-SiC-SB-FET. In addition, we also investigate the effects of non-ideal filling conditions and temperature variations on its performance in practical applications, and conclude that the DSDD-SB-FET biosensor has excellent sensing performance in practical applications as well.

In this work, the effect of p-type doping on the structural, electronic, and optical properties of Al_xGa_1-xAs nanowires are investigated by first-principles calculations. Different doping elements (Be, Mg, Zn), doping methods (interstitial and substitution doping) and doping concentration are considered. The calculations of formation energy suggest that the structural stability of p-type Al_xGa_1-xAs nanowires is gradually weaken as the rise of doping concentration and Al composition. Besides, the difficulty of forming substitution doping for different doping elements obeys the following order: Be < Mg < Zn. In addition, the substitution doping atom tends to replace Ga atom rather than Al atom to form substitution doping structure. After substitution doping, all energy bands shift to higher energy region due to the orbital hybridization of electronic states induced by impurity atom and nanowire atoms. Moreover, the substitution doping leads to the Fermi level entering into the valence band, resulting in obviously p-type conductivity. The p-type modulation doping is indeed effective in the axial type Al_xGa_1-xAs nanowires with p-type carrier concentration varying between 1.85 × 10²⁰ cm⁻³ and 4.42 × 10²⁰ cm⁻³, and the conductivity will be further enhanced with increasing substitution doping concentration or Al composition. Finally, the optical absorption of Al_xGa_1-xAs nanowire photocathodes can be effectively enhanced through Be_Ga doping. Our findings not only present a comprehensive understanding of p-type doping mechanism of Al_xGa_1-xAs nanowires, but also provide a theoretical basis for preparing Al_xGa_1-xAs nanowire based photoelectric devices with p-type properties.

We investigate the digital, analog/RF, and linearity performance of four CP FinFETs distinguished by spacer layers: (i) single low-k spacer on both sides of the gate (D₁), (ii) single high-k spacer on both sides of the gate (D₂), (iii) a combination of high-k spacer and air on the source side and high-k spacer on the drain side (D₃), and (iv) a combination of high-k spacer and air symmetrically placed on both sides of the gate (D₄) at 10 nm technology node. Our results highlight the superior digital performance of the D₄ device, demonstrating significant enhancements in various analog/RF figures of merit (FOMs) including transconductance, transconductance efficiency, unity gain cut-off frequency (F_T), and gain bandwidth product (GBP). Notably, the D₄ device exhibits a remarkable 256 % improvement in F_T and a substantial 456.13 % enhancement in GBP compared to D₁. Additionally, we analyze linearity and intermodulation distortion performance, suggesting the D₄ device as the optimal architecture for high-performance digital and analog/RF applications.

A material like CZTSSe, belonging to the Kesterite family, serves as a guiding light for researchers due to its ability to tunable bandgap and exhibit a high optical coefficient exceeding 10⁴ cm⁻¹, crucial for solar cell applications. These characteristics not only render it suitable for single-junction solar cells but also enhance its overall acceptance. Meanwhile, the material Cu₂ZnSn(S_x, Se_1-x)₄ (CZTSSe) has increasingly captivated the attention of researchers owing to its cost-effectiveness, eco-friendliness, high absorption coefficient, and adjustable bandgap. This paper explores the conventional structure of CZTSSe solar cells comprising Al:ZnO/Zn(O,S)/CZTSSe/different Cu-based HTL, underscoring the importance of identifying an optimal HTL. Consequently, a comparative analysis of solar cells with various HTLs is conducted, facilitated by the SCAPS-1D numerical simulation software for property evaluation and efficiency optimization. Furthermore, varying parameters such as absorber layer thickness, defect densities, doping concentrations, and temperature shed light on the responses of open-circuit voltage (V_OC), short-circuit current (J_SC), fill factor (FF), and efficiency (PCE) of the solar cell. Among different Cu-based HTLs, Cu₂O emerges as a promising candidate for maximizing CZTSSe-based solar cell performance. Additionally, the discussion delves into the impacts of layer parameters like thickness, doping density, and carrier concentrations. Following device optimization, considerations extend to operating temperature variations and the effects of series and shunt resistance. Notably, our endeavors culminate in cell performance metrics: efficiency = 30.65 %, short-circuit current density = 42.15 mA/cm², open-circuit voltage = 0.84 V, and fill factor = 85.60 %.

This work presents specific exploration on the novel gate stack strategies for the intriguing Ge p-MOSFET, where high pressure oxidation (HPO) process is utilized for sufficient oxidation and thus fewer oxygen vacancies, while yttrium doping is developed to strengthen the dielectric bonding for higher ruggedness. Superior gate controllability and stability have been achieved correspondingly, where then detailed comparison on the gate dielectric reliability is conducted. The HPO based GeO₂ gate stack exhibits larger susceptibility to the gate bias stress, and could even breakdown under negative bias, which has been attributed to the local bond breakage that facilitates the irreversible network change. The yttrium-doped GeO₂, on the other hand, presents impressive ruggedness against gate bias stress. Based on detailed bond breakage analysis, cation-doping in GeO₂ is suggested to be effective in enhancing the bond rigidness, promising for a wider safe operation range for the gate bias in Ge MOSFET.

In this work, Artificial Neural Network (ANN) algorithm is used to predict the current conduction mechanisms into the metal-semiconductor (MS) and metal-nanocomposite-semiconductor (MPS) structures along with their primary electronic parameters, such as the leak current (I₀), potential barrier height (Φ_B0), ideality factor (n), series/shunt resistance (R_s/R_sh), rectifying ratio (RR), and interface states density (N_ss) by analyzing the I–V characteristics. The polyvinylpyrrolidone (PVP), barium titanate (BaTiO₃) and graphene (Gr) nanoparticles are mixed together to create the interfacial nanocomposite layer. Training data for ANN algorithm is gathered using the thermionic emission hypothesis. In order to study the efficacy of the ANN model, the predictive power of the ANN technique for predicting the current conduction mechanisms and electronic properties of SDs has been assessed by comparing the predicted and experimental results. The ANN predictions of the current conduction mechanisms at the forward/reverse bias and the fundamental electronic specifications of the MS and MPS structures are a high level of agreement with the experimental results. Furthermore, the results show that the RR and R_sh rise whereas the n, R_s, and N_ss for MS structure decrease when the PVP:Gr-BaTiO₃ nanocomposite interlayer is employed.

This paper investigates the electrical and opto-sensing analysis of hetero stack vertical TFETs based on III/V group Gallium antimonide (GaSb)-Si at various wavelengths within the visible spectrum. Initially, the drain current, energy band diagram, and electron density contour plot are extracted in order to study the DC and electrical behavior of the device. Following that, their performance is evaluated by altering the source side thickness and observe the tunneling rate of device. Furthermore, the photo application of the device is noticed by computing the critical optical parameter such as sensitivity (Sn), noise factor, and efficient characteristics. Finally, a comparative table is included to set the benchmark and highlight the importance of hetero stack TFET. The device's maximum reported sensitivity is approximately 25.2 and responsivity (R) is 0.8 A/Watt at 320 nm wavelength. Additionally, we examined the effect of trap charges under light state at the gate-channel, isolator-channel, and source-channel interface respectively.

Square-shaped BiFeO₃ (BFO) thin films were prepared on SrTiO₃ (STO) substrates by off-axis magnetron sputtering using La_0.5Sr_0.5CoO₃ (LSCO) as the bottom electrode, and both LSCO and BFO are perovskite structure. The BFO crystalline quality improves and the grain size becomes larger as the thickness H increases, and both have smaller mean square roughness. The effects of BFO thickness H, light intensity I_p and ambient temperature AT on the ferroelectric photovoltaic effect (FPE) for the Pt/BFO/LSCO heterostructures are significant. With the H increase, the open-circuit voltage V_oc and short-circuit current J_sc increase linearly, with V_oc up to 0.44 V. The short-circuit current modulation intensity ΔJ_sc follows the ΔJ_sc-300>ΔJ_sc-200>ΔJ_sc-100 rule. With the I_p increase, Pt/BFO(300 nm)/LSCO’ J_sc increases linearly, and V_oc first increases and then tends to saturation, which satisfies Glass' law. With the AT increases, V_oc is linearly decreasing and J_sc shows the law: decreasing→increasing→decreasing. The polarization-modulated FPE mechanism is investigated by analyzing the Pt/BFO/LSCO energy band structure, which is attributed to the coupling effect between the BFO depolarization field (E_dp) and the built-in electric field at the interface (E_Pt/BFO & E_BFO/LSCO), and the FPE mechanism is shifted from the interface barrier domination to the ferroelectric polarization domination as H increases.