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Host Sensitized Lanthanide Photoluminescence from Post-synthetically Modified Semiconductor Nanoparticles Depends on Reactant Identity
摘要： This work investigates the photoluminescence characteristics where cadmium selenide (CdSe) and zinc sulfide (ZnS) nanoparticles are treated post-synthetically by the trivalent lanthanide cations (Ln3+) [Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb] separately to form either CdSe/Ln or ZnS/Ln nanoparticles. Host sensitized Ln3+ emission was found to be present only in CdSe/Eu, CdSe/Tb, ZnS/Eu, ZnS/Tb and ZnS/Yb nanoparticles. In all the cases tuning of emission of the nanoparticles has been observed, irrespective of the presence or absence of host sensitization. The elemental compositions of CdSe and ZnS nanoparticles upon post-synthetic treatment show a remarkable difference. Incorporation of lanthanides in the nanoparticles is evident with significant alteration in the anionic content, and complete cation exchange of either Cd2+ or Zn2+ by Ln3+ has not been detected; as evaluated from energy dispersive X-ray spectroscopy. Further evaluation on this comes from considering thermodynamic parameters of inter cation interaction. In cases where the host sensitized Ln3+ emission have been observed, luminescence lifetime measurements reveal significant protection of Ln3+ in the nanoparticles. Noticeable difference in photophysical properties for a given Ln3+ has been realized in the two hosts. The photophysical observations have been rationalized using (i) charge trapping mediated host sensitized dopant emission, (ii) autoionization of excited electrons, and (iii) environment induced photoluminescence quenching. The post-synthetic modification discussed in the present work provides an easy and less synthetically demanding room temperature based protocol to avail lanthanide incorporated (doped) semiconductor nanoparticles that can potentially use the unique emission properties of the lanthanide cations.
关键词： Semiconductor Nanoparticles,Host Sensitization,Trivalent Lanthanides,Photoluminescence,Post-synthetic Modification
更新于2025-09-23 15:23:52
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Critical impact of gate dielectric interfaces on the trap states and cumulative charge of high-performance organic thin field transistors
摘要： In the operation of OFETs, the electrical properties are strongly dependent on the merits of the constituting layers and the formed interfaces. Here we study the trap states variations at the interface between the organic semiconductor pentacene and polymer insulators. With ZrO2 dielectric modified by polymers and find a 10 × decrease in the density of trap states at the semiconductor/insulator interface, bring about the charge carrier mobility increase from 0.058 cm2/Vs to 0.335 cm2/Vs. In addition, when compare to the thicker films at the same applied gate voltage, the thinner film would lead to enhanced coupling capability and more charges cumulative cumulated at the channel region, which is pivotal for optimizing the performance of OFETs. The results prove that the property of the insulator layer could impact largely on the device performance.
关键词： Organic thin film transistor,Cumulative charge,Insulator/semiconductor interface,Trap states
更新于2025-09-23 15:23:52
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Deep p-ring trench termination: An innovative and cost-effective way to reduce silicon area
摘要： A new type of high voltage termination, namely the 'deep p-ring trench' termination design for high voltage, high power devices is presented and extensively simulated. Termination of such devices consumes a large proportion of the chip size; the proposed design concept not only reduces the termination silicon area required, it also removes the need for an additional mask as is the case of the traditional p+ ring type termination. Furthermore, the presence of the p-ring under and around the bottom of the trench structure reduces the electric field peaks at the corners of the oxide which results in reduced hot carrier injection and improved device reliability.
关键词： Termination,High Voltage,Power Semiconductor Devices
更新于2025-09-23 15:23:52
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Effects of Proton Radiation-Induced Defects on Optoelectronic Properties of MoS2
摘要： We report on photoluminescence spectroscopy and transmission electron microscope imaging of suspended and substrate-supported flakes of the 2D semiconductor MoS2 before and after exposure to 100 keV proton radiation with fluences of 6x1013, 6x1014, and 6×1015 p/cm2 and subsequent annealing. An indirect-to-direct band gap transition is observed, which is preserved after annealing. This transition is accompanied by an unexpected increase in photoluminescence intensity after radiation exposure of multi-layer samples, which is attributed to higher radiative efficiency of the direct gap transition.
关键词： surface wettability,Transition metal di-chalcalgenide,proton radiation,semiconductor nanostructures
更新于2025-09-23 15:23:52
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A comprehensive study on the interface states in the ECR-PECVD SiO2/p-Si MOS structures analyzed by different method
摘要： The electrical properties of SiO2/p-Si films deposited by ECR-PECVD were studied at different frequencies (100-1 MHz) and gate voltages (-6–3 V). Results showed a frequency dispersion of C-Vg and G/ω-Vg. With increasing frequency, the capacitance and conductance are strongly decreased. An apparent peak in the depletion regime of the G/ω-Vg plots can be attributed to the existence of density Nss at Si/SiO2. The (Nss)value vary from 1.5 × 10^12 to 0.5 × 10^11 eV^-1 cm^-2, it has been determined by High-Low frequency capacitance technic. The Nss- Vg curve presents a peak at about -3 V, suggesting the presence Nss between the (Si)/SiO2 interface. Hill and Coleman method shows that the Nss decreases with increasing frequency which explains the high value of capacitance at low frequency. The Nss and their relaxation time τ by the conductance method ranged from 1.8 × 10^13 to 1.37 × 10^11 eV^-1 cm^-2 and 5.17 × 10^-7 to 8 × 10^-6 s, in the range (0.189-Ev) and (0.57- Ev) eV, respectively. The Nss was responsible for the non-ideal behavior of C-Vg and G-Vg leading to the breakdown of such device. Comparing the three method results show that parallel conductance is very precise and accurate.
关键词： Capacitance method,Relaxation time,Frequency,Interface states,Metal/Oxide/Semiconductor (MOS),Conductance method
更新于2025-09-23 15:23:52
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[IEEE 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Novosibirsk, Russia (2018.10.2-2018.10.6)] 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Universal Control System of a Semiconductor Electric Energy Converter on Programmable Logic Devises
摘要： The article presents the results of the development of a universal control system for semiconductor power converters based on a programmable logic devices (PLD). As a result of the work done, shared functional modules for the various control systems of semiconductor converters were determined, the features of implementing modules on programmable logic were considered, and the algorithms for controlling converters on mathematical models were studied. The principal circuit diagram of the universal control system of the converter is synthesized on the basis of a combination of programmable logic devises and a microcontroller. The topologies of printed circuit boards and their layout in a single module of the universal control system of the converter are developed; the built-in microcontroller software was written and debugged in the assembler language. An experimental sample of the control system was made and its joint tests with a prototype of a low-power three-phase inverter equipped with a load simulator were carried out, oscillograms of control pulses and output voltage were obtained in various modes of inverter control.
关键词： digital control system,programmable logic device,algorithm,semiconductor power converter,model
更新于2025-09-23 15:23:52
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Defect formation of CuI-doped by group-IIB elements
摘要： First-principles calculations have been performed to investigate the doping defects in CuI with group-IIB elements such as Zn, Cd and Hg. The calculated transition energies for substitutional Zn, Cd and Hg are 1.32, 1.28 and 0.60 eV, respectively. These group-IIB elements at the substitutional sites complex with a copper vacancy (VCu) have the lower formation energies as compared to dopants located at the substitutional sites or interstitial sites, respectively. Among all the complex defects considered, [HgCu + VCu] has the lowest formation energy and it induces the acceptor level ε(0/?) = 0.18 eV above the valence-band maximum (VBM), which is close to the acceptor level ε(0/?) = 0.1 eV of VCu, suggesting that Hg may be a good dopant for CuI to improve its p-type conductivity.
关键词： group-IIB elements,defects formation,first-principles calculation,Semiconductor
更新于2025-09-23 15:23:52
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Photocathodic hydrogen evolution from catalysed nanoparticle films prepared from stable aqueous dispersions of P3HT and PCBM
摘要： Photo-assisted hydrogen evolution is achieved on photocathodes comprising of nanoparticles of poly(3-hexylthiophene) (npP3HT) and nanoparticles of phenyl-C61-butyric acid methyl ester (npPCBM) onto which ultra-low loadings of Pt nanoparticles are deposited. The nanoparticles, npP3HT and npPCBM, are prepared individually via miniemulsion using surfactants of opposite head group polarity. Aqueous dispersions of npP3HT:npPCBM, devoid of organic solvent, are cast conformally onto ITO-coated glass to yield water-insoluble bulk-heterojunction films. Pt is deposited photoelectrochemically onto ITO/npP3HT:npPCBM photocathodes and found to nucleate preferentially on PCBM nanoparticles. ITO/npP3HT:npPCBM/Pt photocathodes produce 65 μA/cm2 photocurrent under 100 mW/cm2 of visible light at 0.0 VSHE and liberate H2 gas. The photocurrents observed for electrodes prepared using npP3HT:npPCBM are twice as large, and the onset potential is ～0.4 V more positive than analogous photocathodes cast from nanoparticles each comprising an intimate blend of P3HT and PCBM. These are encouraging results for large scale synthesis of organic photoelectrochemical devices, given the simplicity of the photoelectrode, i.e., prepared from aqueous solutions and devoid of vacuum-deposited films such as charge transport layers and protective films.
关键词： Polymer nanoparticle,Photoelectrochemistry,P3HT: PCBM bulk-heterojunction,Solar hydrogen generation,Organic semiconductor,Mini-Emulsion
更新于2025-09-23 15:23:52
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Asymmetric Pentacenes for Solution-Processed Organic Field-Effect Transistors
摘要： Background: Symmetrically substituted pentacenes have been traditionally used as semiconductors for solution-processed p-channel Organic Field Effect Transistors (OFETs). The aims of this paper are to introduce asymmetrically substituted pentacenes in the active layer and to examine the impact of the polyaromaticity of the pendant groups on the device characteristics. Methods: Research and online content related to asymmetrically substituted pentacenes is reviewed, the synthesis of the different pentacenes is described and the procedure used to introduce these semiconductors in devices is detailed. Comparison with a reference material is provided. Results: Extension of the polyaromaticity of the pendant group of pentacene greatly contributes to enhance the device performances. Impact of the pendant group on the morphology of the active layer is evidenced by the roughness decreasing with the increase of aromatic ring in the substituent. Conclusion: We demonstrate the extension of the π-conjugation of the aromatic end-group to drastically impact both ON/OFF ratio and charge carrier mobilities, mainly due to various degree of crystal formation characteristics in the film. Best results were obtained with the most extended one, namely the anthracene moiety which showed a mobility comparable to that of the benchmark TIPS-pentacene with OFETs that used hexamethyldisilazane as the gate dielectric passivation layer.
关键词： solution-process,semiconductor,organic materials,OFET,Mobility,TIPS-pentacene
更新于2025-09-23 15:23:52
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Tuning Material Properties of ZnO Thin Films for Advanced Sensor Applications
摘要： We report on the growth of ZnO thin films by plasma-enhanced atomic layer deposition as a function of substrate temperature. The method to ensure self-limiting growth with precise thickness control is discussed and the effect of temperature on the texture of the thin films is presented. Switching the texture from (100) to (002) by increasing the substrate temperature is a key property for functional devices. The ZnO thin films with tailored properties could find applications in a wide range of sensors and actuators.
关键词： atomic layer deposition,ZnO,thin film,semiconductor
更新于2025-09-23 15:23:52