- 标题
- 摘要
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- 实验方案
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A Machine‐Learning Based Design Rule for Improved Open‐Circuit Voltage in Ternary Organic Solar Cells
摘要： Organic solar cells (OSCs) based on ternary blend active layers are among the most promising photovoltaic technologies. To further improve the power conversion efficiency (PCE), the materials selection criteria must be focused on achieving high open-circuit voltage (Voc) through the alignment of the energy levels of the ternary blend active layers. Hence, machine-learning approaches are in high demand for extracting the complex correlation between Voc and the energy levels of the ternary blend active layers, which are crucial to facilitate device design. In the present work, the data-driven strategies are used to generate a model based on the available experimental data and the Voc are then predicted using available machine-learning methods (Random Forest regression and Support Vector regression). In addition, the Random Forest regression is compared with Support Vector regression to demonstrate the superiority of Random Forest regression for Voc prediction. The Random Forest regression is then developed to find the appropriate energy level alignment of ternary OSCs and to reveal the relationship between Voc and electronic features. Finally, an analysis based on the ranking of variables in terms of importance by the Random Forest model is performed to identify the key feature governing the Voc and the performance of ternary OSCs. From the perspective of device design, the machine-learning approach provides sufficient insights to improve the VOC and advances the comprehensive understanding of ternary OSCs.
关键词： organic field-effect transistors,Machine-learning,charge transport mobility.
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - The Multi-Criteria Optimization in the LTspice Simulation Software of a JFet class AB Buffer Amplifier for Operation at Low Temperatures
摘要： A high-speed buffer amplifier (BA) for analog microcircuits field-effect transistors is proposed. The scheme differs from the known circuit solutions by a small number of elements and can operate within the range of cryogenic temperatures. In the LTSpice simulation software, the optimal control parameters were selected using the DEAP (Distributed Evolutionary Algorithm in Python) library of distributed evolutionary calculations and the NSGA-II multi-criteria optimization algorithm. Minimization of offset voltage, static current consumption and dead band width on the amplitude characteristic at low temperatures were chosen as the priority parameters of the control unit.
关键词： low-temperature electronics,class AB operation,optimization of analog electronic circuit,operational amplifier,LTspice environment,buffer amplifier,junction field-effect transistors
更新于2025-09-12 10:27:22
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High-performance p-channel thin-film transistors with lightly doped n-type excimer-laser-crystallized germanium films
摘要： High-performance polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) fabricated with lightly doped Ge thin films by excimer laser crystallization (ELC) and counter doping (CD) have been demonstrated. High-quality n-type Ge thin films with a grain size as large as 1 μm were fabricated by ELC in the super lateral-growth regime and CD at a dose of 1 × 1013 cm?2 or higher. Consequently, a superior field-effect mobility of 271 cm2 V?1 s?1 and a high on/off current ratio of 2.7 × 103 have been obtained for p-channel Ge TFTs with the channel width and length of both 0.5 μm fabricated by ELC at 300 mJ/cm2 and CD at a dose of 1 × 1013 cm?2. The effects of ELC conditions and CD dose on the electrical characteristics of p-channel Ge TFTs were also investigated.
关键词： field-effect mobility,excimer laser crystallization,thin-film transistors,polycrystalline-germanium,counter doping
更新于2025-09-11 14:15:04
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A new ultra-scaled graphene nanoribbon junctionless tunneling field-effect transistor: proposal, quantum simulation, and analysis
摘要： In this paper, a new ultrascaled junctionless graphene nanoribbon tunnel field-effect transistor (JL GNRTFET) is proposed through a computational study. The quantum simulation approach is based on the resolution of the Schr?dinger equation using the mode space non-equilibrium Green’s function formalism coupled self-consistently with a Poisson equation in the ballistic limit. The proposed nanodevice is endowed with ungated region between the auxiliary and control gates as well as with a laterally graded channel doping in order to improve the switching performance of the ultrascaled junctionless GNRTFET. The performance assessment has included the IDS–VGS transfer characteristics, subthreshold swing, current ratio, intrinsic delay, and power-delay product. It has been found that the proposed ultrascaled junctionless GNR tunneling FET can provide improved switching performance than its conventional counterpart. The proposed strategy can be applied to improve similar ultrascaled junctionless tunneling field-effect transistors for the future digital electronics, where the high-performance and the aggressive downscaling should be in agreement.
关键词： Junctionless,Graphene nanoribbon (GNR),Tunneling field-effect transistor (TFET),Switching,Quantum simulation,Tunneling
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - P-type SiOx front emitters for Si heterojunction solar cells
摘要： We have applied p-type nanocrystalline silicon-oxide (p-SiOx) as front emitter in silicon heterojunction solar cells. The evolution of structural, optical, and electrical properties of p-SiOx as a function of the carbon-dioxide/silane flow rate ratio used in the gas mixture has been investigated, comparing also the film characteristics with those of p-type amorphous and nanocrystalline silicon thin films often used in the cells. Selected p-SiOx films with suitable electrical properties have been inserted in silicon heterojunction solar cells based on n-type FZ c-Si <100> wafers, passivated with ultrathin intrinsic a-Si:H buffers. Improvement of all the photovoltaic parameters has been observed with the emitter with higher oxygen content. The results have been correlated with the increased transparency and enhanced field-effect passivation obtained thanks to the presence of sufficient carbon dioxide in the gas mixture for the p-SiOx layer growth.
关键词： field-effect passivation,silicon heterojunction solar cells,p-type nanocrystalline silicon-oxide,optical and electrical properties,carbon-dioxide/silane flow rate ratio
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - Investigations on HI Reduced Graphene Based FET for Photon Detection
摘要： Reduced graphene oxide-based field effect transistor is fabricated and tested for detection of UV photons in 100-280 nm range. A novel technique is used for reduction of Graphene oxide. The fabricated device showed promising response to UV photons in terms of resistance change in rGO.
关键词： Reduced graphene oxide,UV photon detector,XRD,Field Effect Transistor,Raman spectroscopy
更新于2025-09-11 14:15:04
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Layer-Dependent Optoelectronic Properties of 2D van der Waals SnS Grown by Pulsed Laser Deposition
摘要： Layered metal monochalcogenides have attracted significant interest in the 2D family since they show different unique properties from their bulk counterparts. The comprehensive synthesis, characterization, and optoelectrical applications of 2D-layered tin monosulfide (SnS) grown by pulsed laser deposition are reported. Few-layer SnS-based field-effect transistors (FETs) and photodetectors are fabricated on Si/SiO2 substrates. The premium 2D SnS FETs yield an on/off ratio of 3.41 × 106, a subthreshold swing of 180 mV dec?1, and a field effect mobility (μFE) of 1.48 cm2 V?1 s?1 in a 14-monolayer SnS device. The layered SnS photodetectors show a broad photoresponse from ultraviolet to near-infrared (365–820 nm). In addition, the SnS phototransistors present an improved detectivity of 9.78 × 1010 cm2 Hz1/2 W?1 and rapid response constants of 60 ms for grow-time constant τg and 10 ms for decay-time constant τd under extremely weak 365 nm illumination. This study sheds light on layer-dependent optoelectronic properties of 2D SnS that promise to be important in next-generation 2D optoelectronic devices.
关键词： phototransistors,field effect transistors,2D materials,tin monosulfide,p-type FETs
更新于2025-09-11 14:15:04
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Ambipolar and Robust WSe <sub/>2</sub> Field‐Effect Transistors Utilizing Self‐Assembled Edge Oxides
摘要： Transition metal oxides (TMOs) with high work function (WF) show promising properties as unipolar p-type contacts for transition metal dichalcogenides. Here, ambipolar field-effect transistors (FETs) enabled by bilayer WSe2 with self-assembled TMOs (WO2.57) as contacts are reported. Systematic material characterizations demonstrate the formation of WO2.57/WSe2 heterojunctions around nanoflake edges with Se atoms substituted by O atoms after air-exposure, while pristine properties of WSe2 almost sustain in inner domains. As-fabricated FETs exhibit both polarities, implying WO2.57 with lowered WF at edges can serve as both the p-type and n-type contact for inner WSe2. Noteworthy, greatly reduced contact resistance and enhanced channel current are achieved, compared to the devices without WO2.57 contacts. Linear drain–source current relationship from 77 to 300 K indicates the ohmic contact between edge WO2.57 and inner WSe2. Density functional theory calculations further reveal that the WO2.57/WSe2 heterojunction forms a barrier-less charge distribution. These nm-scale FETs possess remarkable electrical conductivity up to ≈2600 S m?1, ultra-low leakage current down to ≈10?12 A, robustness for high voltage operation, and air stability, which even outperform pristine WSe2 FETs. Theoretical calculations reveal that the high conductivity is exclusively attributed to the air-induced WO2.57 and its further carrier injection to WSe2.
关键词： field-effect transistors,self-passivation,WOx,density functional theory,WSe2
更新于2025-09-11 14:15:04
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Effect of space charge limited current on performance of organic field-effect transistors
摘要： The crucial parameter that determines the performance of a semiconductor material in organic field-effect transistors (OFETs) is the charge carrier mobility. The conventional method of its determination based on Shockley’s equations can lead to incorrect mobility evaluation due to contact effects. Particularly, in the common staggered OFET architecture (top-contact bottom-gate or bottom-contact top-gate), the space-charge limited current (SCLC) effect in the active layer under/above the source and drain contacts decreases the source-drain current. In this work, we model the effect of SCLC under/above the source and drain electrodes on the OFET apparent mobility (i.e., calculated from the device characteristics) and apparent threshold voltage for different active layer thickness and intrinsic mobility anisotropy. For the saturation regime, we derived simple analytical expressions for transfer characteristics and apparent mobility. Our modeling shows that the apparent OFET mobility is more than five times lower than the intrinsic one for the active layer thicker than 100 nm with mobility anisotropy (along vs across the active layer) higher than 100. While the SCLC effect does not change the apparent threshold voltage, it reveals itself as a kink at near zero voltage in the output characteristics. The proposed model gives analytical expressions for the transfer characteristics and apparent mobility as explicit functions of the intrinsic mobility and the device parameters in the saturation regime and as implicit functions in the linear regime. Our findings provide guidelines for accurate evaluation of the intrinsic mobility in OFETs fabricated in the staggered architecture and for further improvement of OFET performance.
关键词： Organic field-effect transistors,Organic thin-film transistors,Space charge limited current,Contact effects,Modeling
更新于2025-09-11 14:15:04
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Highly sensitive air stable easily processable gas sensors based on Langmuir-Schaefer monolayer organic field-effect transistors for multiparametric H <sub/>2</sub> S and NH <sub/>3</sub> real-time detection
摘要： A combination of low limit of detection, low power consumption and portability makes organic field-effect transistors (OFETs) chemical sensors promising for various applications in the areas of industrial safety control, food spoilage detection and medical diagnostics. However, the OFET sensors typically lack air stability and restoration capability at room temperature. Here we report on a new design of highly sensitive gas sensors based on Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene. The devices fabricated are able to operate in air and allows an ultrafast detection of different analytes at low concentrations down to tens ppb. The sensors are reusable and can be utilized in real-time air quality monitoring systems. We show that a direct current response of the LS OFET can be splitted into the alteration of various transistor parameters, responsible for the interactions with different toxic gases. The sensor response acquiring approach developed allows distinguishing two different gases, H2S and NH3, with a single sensing device. The results reported open new perspectives for the OFET-based gas-sensing technology and pave the way to easy detection of the other types of gases enabling the development of complex air analysis systems based on a single sensor.
关键词： Multiparametric detection,Sensing mechanism,Monolayer organic field-effect transistors,Langmuir-Schaefer monolayers,Chemical sensors
更新于2025-09-11 14:15:04