- 标题
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- 实验方案
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Trap and 1/f-noise effects at the surface and core of GaN nanowire gate-all-around FET structure
摘要： Using capacitance, conductance and noise measurements, we investigate the trapping behavior at the surface and in the core of triangular-shaped one-dimensional (1D) array of GaN nanowire gate-all-around field effect transistor (GAA FET), fabricated via a top-down process. The surface traps in such a low dimensional device play a crucial role in determining the device performance. The estimated surface trap density rapidly decreases with increasing frequency, ranging from 6.07 × 1012 cm?2·eV?1 at 1 kHz to 1.90 × 1011 cm?2·eV?1 at 1 MHz, respectively. The noise results reveal that the power spectral density increases with gate voltage and clearly exhibits 1/f-noise signature in the accumulation region (Vgs > Vth = 3.4 V) for all frquencies. In the surface depletion region (1.5 V < Vgs < Vth), the device is governed by 1/f at lower frequencies and 1/f 2 noise at frequencies higher than ~ 5 kHz. The 1/f 2 noise characteristics is attributed to additional generation–recombination (G–R), mostly caused by the electron trapping/detrapping process through deep traps located in the surface depletion region of the nanowire. The cutoff frequency for the 1/f 2 noise characteristics further shifts to lower frequency of 102–103 Hz when the device operates in deep-subthreshold region (Vgs < 1.5 V). In this regime, the electron trapping/detrapping process through deep traps expands into the totally depleted nanowire core and the G–R noise prevails in the entire nanowire channel.
关键词： gate-all-around field effect transistor (FET),trap,nanowire,GaN,1/f-noise
更新于2025-09-23 15:22:29
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Tunable Schottky barriers in ultrathin black phosphorus field effect transistors via polymer capping
摘要： It is still a great challenge to avoid the degradation of ultrathin black phosphorus (BP) since its discovery in 2014. Various methods have been explored to stabilize the properties of ultrathin BP through capping technology or chemical passivation. Besides, the large metal-semiconductor contact resistance is also one of the critical issues. The two problems hinder the further development of ultrathin BP devices. Herein, we demonstrate that polymethyl methacrylate (PMMA) capping can not only enhance the durability of the ultrathin BP effectively and nondestructively, but also tune the effective Schottky barriers (SBs) formed at the interfaces between the metal and semiconductor dramatically. Particularly, the Schottky barrier (SB) for electron injection from metal to semiconductor is decreased by ~ 13 meV and the performance of the BP field effect transistor (FET) is strongly enhanced with the current on/off ratio increased by 6.8 times for the hole conduction after the PMMA capping. In addition, after the electron beam irradiation to the PMMA layer, the charge neutral point of the BP FET exhibits remarkable negative shift resulting in the electron dominated semiconductor channel at zero gate voltage. Furthermore, through partially capping the BP channel, a prototype of BP p-n diode was demonstrated with a maximum rectification factor of 21.3. The diode performs quite well with just a quarter of the BP channel capped by the PMMA layer. Our findings suggest that the PMMA capped ultrathin BP would be a promising choice for future device applications.
关键词： PMMA capping,ambipolar field effect transistor,ultrathin black phosphorus,Schottky barrier
更新于2025-09-23 15:22:29
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Effect of the length of a symmetric branched side chain on charge transport in thienoisoindigo-based polymer field-effect transistors
摘要： Compounds consisting of the electron-accepting thienoisoindigo (TIIG) moiety with branched alkyl side chains of various lengths were each copolymerized with thiophenylene vinylene thiophene (TVT) and selenophenylene vinylene selenophene (SVS) donor moieties, to investigate how the length of the side chain between the branch point and backbone affects the microstructure and charge transport of thin films made of these TIIGTVT and TIIGSVS copolymers. All of the organic field-effect devices based on these copolymers exhibited p-type behaviors, and these devices displayed hole mobility values as high as 1.15 cm2/V/s. Interestingly, the longer side chains in both series of TIIGTVT and TIIGSVS copolymers, the more improved was the molecular ordering of the thin films. But the relationship between charge mobility and side chain length differed for these two series of copolymers, a result attributed to differences between the microstructures of their films. The TIIGTVT series showed localized aggregation, with the greater length of the side chain between the branch point and backbone enhancing the charge transport by increasing the quantity and average size of the aggregates. In contrast, the TIIGSVS series showed long-range order, and aggregates that were too large and prevented charge transport.
关键词： side-chain engineering,thienoisoindigo,polymer field-effect transistor,Polymeric semiconductors
更新于2025-09-23 15:21:21
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[IEEE 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Brasov, Romania (2019.11.3-2019.11.6)] 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Stable Operation of an Automotive Photovoltaic System under Moving Shadows
摘要： This paper presents a simple mathematical expression to model the effect of statistical dopant fluctuations on threshold voltage (Vth) of junction field-effect transistors (JFETs). The random discrete doping (RDD) in the active device area is used to derive an analytical model to compute the standard deviation, σ Vth,RDD of the Vth-distribution for any arbitrary channel doping profiles. The model shows that the Vth-variability in JFETs depends on the active device area, channel doping concentration, and the depth of the channel depletion region of the gate/channel pn-junction. The model is applied to compute σ Vth,RDD for symmetric and asymmetric source/drain double-gate n-channel JFETs. The simulation results show that the model can be used for predicting Vth-variability in JFETs.
关键词： statistical dopant fluctuations,random discrete doping,process variability in JFETs,modeling threshold voltage variability,JFET threshold voltage variability,Junction field-effect transistor (JFET)
更新于2025-09-23 15:21:01
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One-step growth of centimeter-scale doped multilayer MoS <sub/>2</sub> films by pulsed laser-induced synthesis
摘要： Recently, two-dimensional MoS2 has attracted interest for applications in electronics, optics, energy storage, and catalysis. Furthermore, n-type or p-type doping of MoS2 can result in improved film properties, thereby expanding the range of applicability. However, the rapid preparation of large-scale MoS2 films and the e?ective doping of such films remain challenging. Herein, we report on a one-step growth method called pulsed laser-induced synthesis (PLIS) that can resolve these challenges and can quickly (5–10 min) prepare centimeter-scale MoS2 films directly and selectively on a substrate. A continuous length of up to 1.412 cm can be achieved with MoS2 films prepared by the described in situ doping of noble metals (Au, Pt, and Pd) to convert MoS2 into a p-type semiconductor was realized, consistent with the results obtained from first-principles calculations. The STEM images reveal that the phenomena of surface modification and cation substitution occur in the doped MoS2 films. The doped MoS2 films were further processed into a p-type field effect transistor with an on/off ratio of 105. Importantly, this technique can be applied to other transition metal dichalcogenides (TMDCs) while employing various doping elements; this scheme provides an innovative method for upscaling production and large-area doping of TMDC thin films.
关键词： TMDCs,MoS2,field effect transistor,doping,pulsed laser-induced synthesis
更新于2025-09-23 15:21:01
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Controlled doping of graphene by impurity charge compensation via a polarized ferroelectric polymer
摘要： A simple technique of doping graphene by manipulating adsorbed impurity charges is presented. Using a field effect transistor configuration, controlled polarization of a ferroelectric polymer gate is used to compensate and neutralize charges of one type. The uncompensated charges of the opposite type then dope graphene. Both n- and p-type doping are possible by this method, which is non-destructive and reversible. We observe a change in n-type dopant concentration of 8 × 1012 cm?2 and a change in electron mobility of 650%. The electron and hole mobilities are inversely proportional to the impurity concentration, as predicted by theory. Selective doping of graphene can be achieved using this method by patterning gate electrodes at strategic locations and programming them independently. Such charge control without introducing hard junctions, therefore, permits seamless integration of multiple devices on a continuous graphene film.
关键词： ferroelectric polymer,doping,graphene,charge compensation,field effect transistor
更新于2025-09-23 15:21:01
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Few-layer PdSe2-based field-effect transistor for photodetector applications
摘要： We demonstrate a multilayer palladium diselenide (PdSe2) high-performance photodetector. The photodetector exhibits the photodetectivity of 0.15 ? 1010 Jones under laser illumination (λ ? 655 nm and power of 0.057 mWmm(cid:0) 2). The negative threshold voltage shift in transfer characteristics upon laser illumination is mainly attributed to the photogating effect. Systematic analysis of experimental data indicates that the photogating effect and space charge limited conduction are simultaneously involved in the conduction mechanism. We observe that the photogenerated current increases logarithmically as the light intensity increases, and it persists (~200 s) even after stopping the illumination. The slow decrease in current was attributed to the trapping of photogenerated charge carriers at the PdSe2/SiO2 interface and the defects in the structure of PdSe2. We also observe a reproducible and stable time-resolved photoresponse with respect to the incident laser power. We believe that this study can be an important source of information and can help researchers to continue to investigate methods that would allow them to maximise the potential of PdSe2 for photodetector applications.
关键词： Palladium diselenide,Photodetector,Field effect transistor,Two-dimensional materials,Photoresponse
更新于2025-09-23 15:21:01
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Resonance Frequency Modulation for Rapid Point-of-care Ebola Glycoprotein Diagnosis with a Graphene-based Field-effect Bio-transistor
摘要： Recent outbreaks of the Ebola virus infection in several countries demand a rapid point-of-care (POC) detection strategy. This paper reports on an innovative pathway founded on electronic resonance frequency modulation to detect Ebola glycoprotein (GP), based on carrier injection-trapping-release-transfer mechanism and standard antibody-antigen interaction principle within a dielectric-gated reduced graphene oxide (rGO) field-effect transistor (GFET). The sensitivity of the current Ebola detection can be significantly enhanced by monitoring the device’s electronic resonance frequency, such as inflection frequency (fi), where phase angle reaches maximum (θmax). In addition to excellent selectivity, a sensitivity of ~36-160 % and ~17-40 % for 0.001-3.401 mg/L Ebola GP can be achieved at high and low inflection resonance frequencies, respectively, which are several orders of magnitude higher than the sensitivity from other electronic parameters (e.g., resistance-based sensitivity). Using equivalent circuit modelling on contributions of channel and contact, analytical equations for resonance shift have been generalized. When matching with the incoming ac measurement signal, electronic resonance from the phase angle spectrum is evolved from various relaxation processes (e.g., trap and release of injected charge at surface trap sites of channel-gate oxide and channel-source/drain interface) that are associated with a characteristic emission frequency. Using charge relaxation dynamics, a high-performance bio-FET sensing platform for healthcare and bio-electronic applications is realized through resonance shifting.
关键词： graphene-based field-effect transistor,Ebola glycoprotein,resonance frequency modulation,point-of-care detection,bio-FET sensing platform
更新于2025-09-23 15:21:01
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Cesium Lead Bromide Quantum Dot Light-Emitting Field-Effect Transistors
摘要： Solution processible perovskite quantum dots are considered as promising optical materials for light emitting optoelectronics. The light-emitting field-effect transistors that can be operated under relatively lower potential with an efficient energy conversion efficiency have yet to be realized with the perovskite quantum dot. Here, we present the CsPbBr3 quantum dot-based light-emitting field-effect transistor (LEFET). Surprisingly, unipolar transport characteristics with strong electroluminescence was observed at the interface of the CsPbBr3 QD-LEFET along with the exceptionally wide recombination zone of 80 μm, an order of magnitude larger than that of organic/polymer light-emitting field-effect transistors. Based on the systematic analysis for the electroluminescence of the CsPbBr3 NC-LEFET, we revealed that the increased diffusion length determined by the majority carrier mobility and the lifetime well explains the remarkably wide recombination zone. Furthermore, it was found that the energy-level matching and transport geometry of the hetero-structure also determine the charge distribution and recombination, substantially affecting the performance of the CsPbBr3 QD LEFET.
关键词： Organic/inorganic hybrid field-effect-transistor,Light emitting field-effect-transistor,Wide recombination zone,Diffusion length,CsPbBr3 quantum dots
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Grain Growth in CdTe Films During CdCl <sub/>2</sub> Treatment: TeCl <sub/>4</sub> Theory
摘要： A diamond metal–semiconductor field-effect transistor (MESFET) with a Pt Schottky gate was fabricated. The MESFET exhibited clear saturation and pinchoff characteristics. The drain current of the MESFET operated at 300 °C was 20 times higher than that at room temperature due to the activation of acceptors. The breakdown voltage was highly dependent on the gate–drain length and reached 1.5 kV at a gate–drain length of 30 μm, which is the highest reported for a diamond FET.
关键词： metal-semiconductor field-effect transistor,Diamond,breakdown voltage
更新于2025-09-23 15:19:57