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Effect of Proton Radiation on Ultra-Wide Bandgap AlN Schottky Barrier Diodes
摘要： Lateral Pd/n-AlN Schottky barrier diodes (SBDs) were fabricated and subjected to 3 MeV proton irradiation at various fluences. Electrical and material characterization analysis was performed before and after each radiation fluence to quantify the change in device characteristics. It was found that the SBDs performed reliably up to a proton irradiation fluence of 5×1013 cm-2, with little or no change in the key device performance such as current, turn-on voltage, ideality factor, and breakdown voltage, etc. The electrical characteristics of the SBDs was well predicted using a standard thermionic emission theory. The performance of the SBDs showed a significant degradation after a high-fluence irritation of 5×1015 cm-2, where the current of the SBDs dropped two orders of magnitude. Material and surface characterizations, including atomic force microscopy and X-ray diffraction, indicated a consistent degradation in the AlN bulk crystal quality and a drastic increase in surface roughness. These results provide valuable information on the radiation properties of AlN electronics and can serve as important references for the future development of high performance AlN devices for extreme environment applications.
关键词： surface roughness,leakage current,radiation effects,Aluminum nitride,breakdown voltage,barrier height,Schottky barrier diodes,ideality factor,turn on voltage
更新于2025-09-11 14:15:04
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Complementary Properties of Silver Nanoparticles on the Photovoltaic Performance of Titania Nanospheres Based Photoanode in Dye-Sensitized Solar Cells
摘要： In this study, the fabrication of photoanode of dye-sensitized solar cell using silver@titania nanospheres and N719 dye, and its enhanced photovoltaic performance in the dye-sensitized solar cell is described. Silver@titania with different mol. % of silver (1, 3 and 5 %) are synthesized using facile sol-gel and photochemical reduction method and are characterized by suitable analytical techniques. The synthesized nanocomposite materials showed nanospheres like morphology. Moreover, photoluminescence studies revealed that incorporation of silver nanoparticles on the titania nanospheres surface suppressed charge recombination process and which is more beneficial for dye-sensitized solar cells. Silver@titania nanospheres are successfully employed as a photoanode and demonstrated an enhanced solar-to-electrical energy conversion efficiency of 5.24 %, under full sun illumination (100 mW cm-2, AM 1.5 G) which is 30.67 % enhancement than that of bare titania nanospheres (4.01 %). This enhanced efficiency is attributed to the rapid interfacial charge transfer process and plasmonic effect offered by silver nanoparticles present in the silver@titania nanospheres. The improved charge transfer process led to minimize the back electron transfer reaction in the device. With complementary properties of silver nanoparticles, the high performance demonstrated by the silver@titania nanospheres could be an excellent candidate for the light energy harvesting applications.
关键词： Dye-sensitized solar cells,Plasmonic nanoparticles,Schottky barrier,Titania nanospheres,Silver nanoparticles
更新于2025-09-11 14:15:04
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Synchronous Enhancement for Responsivity and Response Speed in In2Se3 Photodetector Modulated by Piezoresistive Effect
摘要： Although ultra-high single performance indicators have been achieved based on two-dimensional(2D) semiconductors, the comprehensive performances of the photodetectors of them are not so desirable. Note that the response speed and responsivity are two key figures of merit for photodetectors, while these two parameters are always mutually suppressive and can not be synchronously satisfied. Here, we proposed a feasible strategy that can simultaneously improve the responsivity and response speed of In2Se3-based photodetectors, by applying the mechanical strain and producing the piezoresistive effect, which can synergistically modulate the band structure and boost the overall photodetecting performances. Through studying the optoelectronic properties of In2Se3 photodetector under strain modulations, we found that the responsivity under 0.65% tensile strain is improved by almost 68.6% on average while responsivity under 0.65% compressive strain is lowered by about 57.3% in the wavelength range of 200-1000 nm. More importantly, the response speed of the In2Se3-based photodetector under two different mechanical strains rises distinctly (from 244 to 214 and 180 μs, accordingly). The strain-engineering can accommodate the band structure and enhance the electric and optical properties of the semiconducting crystals, ultimately realizing high-performance photodetectors. The strategy proposed in this work for improving the performance of photodetectors provides a promising route to practical applications in next-generation optoelectronic devices.
关键词： photoconductor,mechanical strain,Schottky barrier,van der Waals,piezoresistive effect
更新于2025-09-11 14:15:04
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New small molecule electrolytes based on tosylate anion for organic solar cells
摘要： Reduction of a Schottky barrier between the active layer and electrodes can play an important role enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs), which originated from a favorable interface dipole at the cathode interface. Herein, two new small molecules (SM) electrolytes based on tosylate anions, named 2,2’-(ethane-1,2-diylbis(oxy))bis(N,N,N-trimethylethananminium) benzenesulfonate (TEG-M-OTs) and 1,1’-bis(1-dodecyl)-4,40-bipyridine-1,10-diium benzenesulfonate (V-C12-OTs), were synthesized to induce the reduction of a Schottky barrier in OSCs. The PCE of devices based on ZnO with TEG-M-OTs or V-C12-OTs as the cathode buffer layer (CBL) was enhanced from 7.48% to 7.74% and 7.88%. In case of ZnO-free devices, the PCE of TEG-M-OTs or V-C12-OTs was achieved up to 4.22% and 6.95%, respectively. The Kelvin probe microscopy was performed by measuring the work function (WF) of SM electrolytes with or without ZnO on the ITO surface. It showed that the WFs of SM electrolytes coated ITO are closer to - 4.02 eV, the lowest unoccupied molecular orbitals (LUMO) of the acceptor, than the WF of MeOH treated ITO with ZnO (- 4.37 eV).
关键词： Schottky barrier,organic solar cells,tosylate anion,power conversion efficiency,small molecule electrolytes
更新于2025-09-11 14:15:04
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Generation and Thermal Properties of a Dual-Transverse-Mode With Dual-Polarization and Dual-Frequency by a Dual-Medium Microchip Laser
摘要： An AlGaN/GaN lateral reverse blocking current regulating diode (RB-CRD) with trench Schottky anode and hybrid trench cathode has been proposed and experimentally demonstrated on silicon substrate. The Schottky barrier diode (SBD) integrated in the anode exhibits a turn-on voltage of 0.7 V and a reverse breakdown voltage of 260 V. The hybrid trench cathode acts as a CRD, which is in series connection with the anode SBD. A knee voltage of 1.3 V and a forward operation voltage beyond 200 V can be achieved for the RB-CRD. The RB-CRD is capable of outputting an excellent steady current in a wide temperature range from 25 to 300 °C. In addition, the forward regulating current exhibits small negative temperature coefficients less than ? 0.152%/oC.
关键词： Reverse blocking current regulating diode (RB-CRD),AlGaN/GaN heterostructure,Schottky barrier diode (SBD)
更新于2025-09-11 14:15:04
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Coulomb scattering mechanism transition in 2D layered MoTe <sub/>2</sub> : effect of high- <i>κ</i> passivation and Schottky barrier height
摘要： Clean interface and low contact resistance are crucial requirements in two-dimensional (2D) materials to preserve their intrinsic carrier mobility. However, atomically thin 2D materials are sensitive to undesired Coulomb scatterers such as surface/interface adsorbates, metal-to-semiconductor Schottky barrier (SB), and ionic charges in the gate oxides, which often limits the understanding of the charge scattering mechanism in 2D electronic systems. Here, we present the effects of hafnium dioxide (HfO2) high-κ passivation and SB height on the low-frequency (LF) noise characteristics of multilayer molybdenum ditelluride (MoTe2) transistors. The passivated HfO2 passivation layer significantly suppresses the surface reaction and enhances dielectric screening effect, resulting in an excess electron n-doping, zero hysteresis, and substantial improvement in carrier mobility. After the high-κ HfO2 passivation, the obtained LF noise data appropriately demonstrates the transition of the Coulomb scattering mechanism from the SB contact to the channel, revealing the significant SB noise contribution to the 1/f noise. The substantial excess LF noise in the subthreshold regime is mainly attributed to the excess metal-to-MoTe2 SB noise and is fully eliminated at the high drain bias regime. This study provides a clear insight into the origin of electronic signal perturbation in 2D electronic systems.
关键词： Coulomb screening,low-frequency noise,Schottky barrier height,molybdenum ditelluride,high-κ passivation
更新于2025-09-10 09:29:36
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Effect of surface passivation process for AlGaN/GaN HEMT heterostructures using phenol functionalized-porphyrin based organic molecules
摘要： In this work, we investigate an unexplored possibility of passivating the charged surface states on AlGaN/GaN high electron mobility transistor (HEMT) heterostructures by using organic molecules. This has further led to remarkable enhancement in the electrical properties of rectifying metal-semiconductor contacts on AlGaN/GaN. Phenol functionalized Zinc metallated-Tetra Phenyl Porphyrin (Zn-TPPOH) organic molecules were adsorbed on AlGaN/GaN via the solution phase to form a molecular layer (MoL). The presence of the MoL was confirmed using X-ray Photoelectron Spectroscopy (XPS). The thickness of the MoL was assessed as ～1 nm, using Spectroscopic Ellipsometry and cross-sectional Transmission Electron Microscopy. XPS peak-shift analyses together with Kelvin Probe Force Microscopy revealed that the molecular surface modification reduced the surface potential of AlGaN by approximately 250 meV. Consequently, the Barrier height (ideality factor) of Ni Schottky diodes on AlGaN/GaN was increased (reduced) significantly from 0.91 ± 0.05 eV (2.5 ± 0.31) for Ni/AlGaN/GaN to 1.37 ± 0.03 eV (1.4 ± 0.29) for Ni/Zn-TPPOH/AlGaN/GaN. In addition, a noteworthy decrement in the reverse current from 2.6 ± 1.93 μA to 0.31 ± 0.19 nA at ?5 V (～10 000 times) was observed from Current-Voltage (I-V) measurements. This surface-modification process can be fruitful for improving the performance of AlGaN/GaN HEMTs, mitigating the adverse effects of polarization and surface states in these materials.
关键词： AlGaN/GaN,HEMT,Schottky barrier height,surface passivation,organic molecules,reverse current
更新于2025-09-10 09:29:36
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Ge Complementary Tunneling Field-Effect Transistors Featuring Dopant Segregated NiGe Source/Drain
摘要： Ge complementary tunneling field-effect transistors (TFETs) are fabricated with the NiGe metal source/drain (S/D) structure. The dopant segregation method is employed to form the NiGe/Ge tunneling junctions of sufficiently high Schottky barrier heights. As a result, the Ge p- and n-TFETs exhibit decent electrical properties of large ON-state current and steep sub-threshold slope (?? factor). Especially, ??d of 0.2 ??A/??m is revealed at ??g ? ??th = ??d = ±0.5 V for Ge pTFETs, with the ?? factor of 28 mV/dec at 7 K.
关键词： ON-state current,NiGe metal source/drain,Ge complementary tunneling field-effect transistors,sub-threshold slope,Schottky barrier heights,dopant segregation
更新于2025-09-10 09:29:36
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Tunable Schottky barrier width and enormously enhanced photoresponsivity in Sb doped SnS2 monolayer
摘要： Doping, which is the intentional introduction of impurities into a material, can improve the metal-semiconductor interface by reducing Schottky barrier width. Here, we present high-quality two-dimensional SnS2 nanosheets with well-controlled Sb doping concentration via direct vapor growth approach and following micromechanical cleavage process. X-ray photoelectron spectroscopy (XPS) measurement demonstrates that Sb contents of the doped samples are approximately 0.22%, 0.34% and 1.21%, respectively, and doping induces the upward shift of the Fermi level with respect to the pristine SnS2. Transmission electron microscopy (TEM) characterization exhibits that Sb-doped SnS2 nanosheets have a high-quality hexagonal symmetry structure and Sb element is uniformly distributed in the nanosheets. The phototransistors based on the Sb-doped SnS2 monolayers show n-type behavior with high mobility which is one order of magnitude higher than that of pristine SnS2 phototransistors. The photoresponsivity and external quantum efficiency (EQE) of Sb-SnS2 monolayers phototransistors are approximately three orders of magnitude higher than that of pristine SnS2 phototransistor. The results suggest that the method of reducing Shottky barrier width to achieve high mobility and photoresponsivity is effective, and Sb-doped SnS2 monolayer has significant potential in future nanoelectronic and optoelectronic applications.
关键词： doping,two-dimensional,SnS2,optoelectronics,Schottky barrier width
更新于2025-09-10 09:29:36
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Thermal characterization of gallium oxide Schottky barrier diodes
摘要： The higher critical electric field of β-gallium oxide (Ga2O3) gives promise to the development of next generation power electronic devices with improved size, weight, power, and efficiency over current state-of-the-art wide bandgap devices based on 4H-silicon carbide (SiC) and gallium nitride (GaN). However, it is expected that Ga2O3 devices will encounter serious thermal issues due to the poor thermal conductivity of the material. In this work, self-heating in Ga2O3 Schottky barrier diodes under different regimes of the diode operation was investigated using diverse optical thermography techniques including thermoreflectance thermal imaging, micro-Raman thermography, and infrared thermal microscopy. 3D coupled electro-thermal modeling was used to validate experimental results and to understand the mechanism of heat generation for the diode structures. Measured topside and cross-sectional temperature fields suggest that device and circuit engineers should account for the concentrated heat generation that occurs near the anode/Ga2O3 interface and/or the lightly doped drift layer under both forward and high voltage reverse bias conditions. Results of this study suggest that electro-thermal co-design techniques and top-side thermal management solutions are necessary to exploit the full potential of the Ga2O3 material system.
关键词： Schottky barrier diodes,thermal characterization,electro-thermal modeling,gallium oxide,optical thermography
更新于2025-09-10 09:29:36