Journal of Computational Electronics最新文献

In this work we studied the effects of negative hydroxyl ions at the SnO₂/perovskite layer interface with respect to the performance of perovskite solar cells (PSCs). We considered a layer of 1 nm thickness, containing fixed negative ions, at the SnO₂/perovskite layer interface. The density of the ions was set to 7 × 10¹⁹ cm⁻³ in our simulations. To maintain charge neutrality in the SnO2 electron transport layer (ETL), we calculated the number of negative ions in the 1-nm-thick layer and added the same number of positive ions to the remaining part of the ETL. According to our simulation results, the negative ions increased the internal potential drop, reducing the open-circuit voltage of the perovskite solar cell from 0.99 to 0.88 V. On the other hand, the negative non-mobile hydroxyl ions at the interface absorbed some of the mobile positive ions of the perovskite layer, which increased the hysteresis index from 0.177% to 0.707%.

Computing in memory (CiM) architecture enables computation within the memory array, reducing power-intensive data transmission between the processor and memory. The primary goal of this work is to enhance the energy efficiency of CiM architectures that use spintronic devices. Experiments show that the thermal stability ((Delta)) in magnetic tunnel junctions (MTJs) can be optimized to reduce write energy by adjusting the oxide layer thickness. Based on this finding, this work explores a novel spin-orbit torque random-access memory (SOT) cell that yields a 30% increase in energy efficiency compared to conventional SOT. However, reducing the oxide layer thickness below 1.5 nm to tune (Delta) leads to a decrease in the tunnel magnetoresistance (TMR) ratio leading to reliability concerns. The second part of the work proposes to improve TMR by replacing the conventional MgO oxide layer with a TiCoSb Heusler alloy-based layer and utilizing (hbox {Co}_{2}hbox {MnSb}) as the electrode in the modified cell called (Delta)M-SOT. Theoretical and experimental studies demonstrate that this alternative MTJ design exhibits TMR ratios comparable to values reported in the literature. The performance of magnetic full adder CiM design using the proposed (Delta)M-SOT is compared with designs implemented using CMOS, spin-transfer torque random-access RAM (STT), and conventional SOT. Evaluations show that the (Delta)M-SOT-CiM has a reduction of 66% and 30% in logic and data transfer energy, respectively, compared to conventional SOT-CiM design. Furthermore, the data storage and computation operations in (Delta)M-SOT-CiM are found to be significantly faster compared to both STT- and SOT-CiM design. Overall, this work presents a promising SOT design that effectively bridges the gap between the processor and memory by enabling logical functions within memory, eliminating the need for additional circuits.

The article offers a comprehensive exposition of the theoretical underpinnings and empirical substantiation pertaining to the energy-reversible nanoelectromechanical switch (NEMS) in the context of adiabatic computing and biomedical applications. Adiabatic circuits employ a power clock consisting of four phases and employ astute circuit configurations to circumvent the accumulation of transistor charge during logic operations, thereby mitigating power consumption. NEM switches exhibit minimal leakage current and demonstrate a low static power consumption profile, rendering them highly suitable for deployment in various electronic devices. The utilization of energy-reversible NEMs witches has the potential to mitigate adiabatic circuit power consumption. The rationale behind this phenomenon lies in the switch ability to preserve and regenerate mechanical bending energy throughout successive cycles, both in the present and in subsequent switching events. The present study aims to investigate the advantages associated with the utilization of NEMS, encompassing both three-terminal and energy-reversible variations, as opposed to CMOS (complementary metal–oxide–semiconductor) transistor switch within adiabatic circuits. This study aims to investigate the dissipation of power clock energy per cycle across a range of frequencies through a comprehensive analysis grounded in theoretical principles and substantiated by empirical evidence. Throughout the course of this investigation, it was observed that the pull-in voltage of energy-reversible NEM switches exhibited a consistent decrease of 13% over consecutive switching cycles. The reduced pull-in voltage results in a decrease in the amount of energy required for switching. In the realm of low-frequency activities that operate at frequencies below 100 kHz, it has been observed that the implementation of noise exclusionary mechanisms has the potential to effectively curtail energy consumption. Henceforth, it is imperative to underscore the primary domains wherein biomedical engineering and low-power applications ought to be accorded paramount significance.

For the conventional super junction trench insulated gate bipolar transistor (SJ-TIGBT), the higher the N/P column doping concentration (N_c), the better the electrical characteristics can be obtained. However, considering the negative impact of charge imbalance of the N/P column on the breakdown voltage (BV), the value of N_c is limited, which limits the improvement of device performances. In this paper, a novel SJ-TIGBT with narrow mesa (NM) and floating-P (FP) region (NMFP-SJ-TIGBT) is proposed. The electrical characteristics of the proposed SJ-TIGBT are significantly enhanced owing to the dual injection enhancement effect provided by the NM and FP region. Moreover, for the proposed SJ device, the excellent performance obtained in the lower N_c regime alleviates the negative impact of charge imbalance of N/P column on the BV, which greatly improves its fabrication process tolerance. The simulation results show that compared to the conventional SJ-TIGBT (SJ-TIGBT-A), a SJ-TIGBT with an n-injector layer (SJ-TIGBT-B) and a SJ-TIGBT with a floating-P column under the gate (SJ-TIGBT-C), the proposed structure demonstrates a significantly lower and almost constant on-state voltage drop (V_ceon). At a collector current density of 100 A/cm² and N_c of 1 × 10¹⁵ cm⁻³, the V_ceon of the proposed SJ-TIGBT is 74.9%, 41.1% and 26.1% lower than that of the SJ-TIGBT-A, SJ-TIGBT-B and SJ-TIGBT-C, respectively. With the same V_ceon of 1.05 V and N_c of 1 × 10¹⁵ cm⁻³, the turn-off loss of the proposed SJ-TIGBT is only 6.44 mJ/cm², which is 73.7% and 35.4% lower than that of SJ-TIGBT-B and SJ-TIGBT-C, respectively.

In this paper, based on the first-principles calculation method of density functional theory, the PtS₂/PtSe₂ heterostructure with the lowest formation energy is selected from five different stacking modes. At the same time, the phonon spectrum of PtS₂/PtSe₂ heterostructure has no imaginary frequency, so the structure is stable. After that, the changes of photoelectric properties of heterostructures under tensile and compressive strains were studied. It is concluded that the PtS₂/PtSe₂ heterostructure is a semiconductor with indirect band gap and type II band arrangement. With the increase of tensile strain, the band gap value decreases from 0.927 to 0.565 eV, and the minimum value of the conduction band is transferred from the high symmetry point M point to the K point by 8% biaxial tensile strain. The biaxial tensile strain can effectively improve the dielectric constant of the PtS₂/PtSe₂ heterostructure. When the strain reaches 8%, the dielectric constant is nearly twice as high as the intrinsic value and reaches 11.6, which improves the charge retention ability. The light absorption of PtS₂/PtSe₂ heterostructure reaches 13.7 × 10⁴ cm⁻¹ under compressive strain, and the stability of light absorption is enhanced. The optical reflection ability of PtS₂/PtSe₂ heterostructure is significantly enhanced under tensile strain, indicating that the biaxial strain has a regulatory effect on the absorption and reflection ability of light. The valley values of all systems near the ultraviolet region show a linear increase trend, which changes the transmittance of the heterostructure. These findings broaden the application of PtS₂/PtSe₂ heterostructures in optoelectronic engineering.

In this work, the influence of heavy ions on the performance mechanism of recess gate GaN/AlN-based p-channel HEMT has been investigated using extensive TCAD simulation. The effect of the recess gate depth and position along with the technological misalignment issues has also been addressed. Results show that the transient drain current is more sensitive to heavy ions when it is incident in the gate–drain access region. Also, the device exhibited high susceptibility to heavy ions, with increasing energy and recess gate depth. With the increase in linear energy transfer (LET) value, the peak gate and drain current increase linearly. Further to make the device more robust against heavy ions, MIS-type configuration in GaN/AlN architecture is studied with silicon nitride as the dielectric layer. The insulating layer provides an additional degree of protection against the single-event effects caused by heavy ions or other sources of charge injection mechanism.

We present the characterization of seven newly developed organic dyes tailored for application in dye-sensitized solar cells (DSSCs). At the core of their structures is 8,10-di(thiophen-2-yl) trithieno[3,4-b:3′,2′-f:2″,3″-h] quinoxaline, serving as the electron-donor group across all dyes. Employing density functional theory (DFT) and time-dependent DFT (TD-DFT) techniques with the CAM-B3LYP level and 6-31G(d,p) basis set, we delved into molecular structures, frontier molecular orbitals (FMOs), and various electronic chemical properties. This investigation is aimed at unraveling their ultraviolet–visible (UV–Vis) absorption properties, electron injection free energy, and global hardness (η), electronegativity (χ), and chemical potential (µ). These insights shed light on the stability and potential utility of these dyes as sensitizers in DSSCs. Furthermore, computation and discussion of the open-circuit voltage (({V}_{OC})) underscored the promising nature of these seven new organic dyes with D-A molecules, positioning them as strong contenders for DSSC applications, all anchored around 8,10-di(thiophen-2-yl) trithieno[3,4-b:3′,2′-f:2',3″-h] quinoxaline as the electron-donor group.

Here, the electronic conductance characteristics of naphthopyran were studied using non-equilibrium Green’s function density functional theory (NEGF-DFT) and time-dependent density functional theory (TD-DFT) methods. When naphthopyran is exposed to UV or visible light, the specified structure can switch between its open and closed forms. Molecular geometries, surface material types (platinum, gold, and silver), switching ratios, gaps between HOMO and LUMO levels, transmission spectra, and PDOS at different bias voltages were studied. It was found that the conductance of naphthopyran changed from an off-state (high resistance) to an on-state (low resistance) when the molecular optical junction converted from the open to the closed configuration.

The current study delves into the physical properties and hydrogen storage capabilities of XScH₃ (X = K, Na) using the CASTEP code by leveraging the GGA-PBE method. The examined values of the lattice constants for KScH₃ and NaScH₃, are 4.19 and 4.07 Å, respectively. With a zero band gap revealing the metallic behavior, both compounds are discovered to be mechanically and thermodynamically stable in the cubic phase. Both compounds exhibit substantially enhanced conductivity and absorption in the low-energy range. While comparing NaScH₃ to KScH₃, the reflectivity and refractive index values for the former are significantly higher. Both the materials possess anisotropic and hard nature represented by anisotropic factor, young’s modulus, bulk modulus and mean shear modulus. Both compounds exhibit the brittle nature which is investigated with the help of poisson ratio and Pugh’s ratio. The values of bulk modulus, young’s modulus and mean shear modulus are higher for KScH₃ than NaScH₃ showing more hardness in KScH₃. The ratio of gravimetric hydrogen storage is found 3.48 and 4.27 wt %, for KScH₃ and NaScH₃, respectively which shows that both materials can accommodate a good amount of hydrogen, however, NaScH₃ can be preferred for hydrogen storage applications due to the higher storage capacity of hydrogen.

First-principles calculations combined with the Boltzmann transport theory were used to calculate the thermoelectric characteristics of Zr_1−xNiSnTa_x (x = 0, 1/4, 1/8, 1/12, 1/16, 1/24, 1/32, 1/36, 1/48, and 1/64). Ta-doped ZrNiSn can effectively improve the Seebeck coefficient of Zr_1−xNiSnTa_x, and it can also reduce its thermal conductivity. The maximum Seebeck coefficients of p-type and n-type Zr_3/4NiSnTa_1/4 are 1117.58 μV/K and − 1059.47 μV/K, respectively. The maximum thermoelectric figure of merit of the p-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.98, and the maximum thermoelectric figure of merit of the n-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.97. The optimum thermoelectric figure of merit of Zr_1−xNiSnTa_x studied in this paper is higher than those of other studies. Our results demonstrate the good potential thermoelectric material of Zr_1−xNiSnTa_x for thermoelectric device applications.