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Effect of Carboxyl-Functionalized Single Walled Carbon Nanotubes on the Interfacial Barrier Height of Malachite Green Dye Based Organic Device
摘要： In this study, we have estimated the interfacial barrier height ((cid:1)b) of Indium Tin Oxide (ITO) coated glass/Malachite Green (MG) dye/Aluminium (Al) based organic device and subsequently we have also observed the effect of carboxylfunctionalized SWCNT (COOH-SWCNT) on the (cid:1)b. Presence of COOH-SWCNT reduces the interfacial barrier height as SWCNT acts as filler and provides easy path for charge percolation. We have used ITO coated glass and aluminium as front electrode and back electrode respectively to form the organic device. This organic device has been prepared with and without COOH-SWCNT by using spin coating technique. We have measured the steady state current-Voltage (I-V) characteristics of the device to estimate the interfacial barrier height ((cid:1)b) of the device. (cid:1)b is reduced from 0.67 eV to 0.59 eV in the presence of COOH-SWCNT. We have also estimated the (cid:1)b by using Norde’s Method. This method also shows a reduction of interfacial barrier height from 0.72 eV to 0.64 eV due to incorporation of COOH-SWCNT. Both the methods show good consistency with each other. Reduction of the interfacial barrier height in presence of COOH-SWCNT indicates the enhancement of charge injection through the metal-organic dye interface. By suitable doping or addition of COOH-SWCNT within the MG dye it is possible to reduce the barrier height and enhance the current injection through metal-organic dye interface.
关键词： Interfacial Barrier Height,Malachite Green Dye,Metal-Organic Dye Interface,COOH-SWCNT
更新于2025-09-12 10:27:22
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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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Gaussian distribution in current-conduction mechanism of (Ni/Pt) Schottky contacts on wide bandgap AlInGaN quaternary alloy
摘要： The current-conduction mechanisms of the as-deposited and annealed at 450 °C (Ni/Pt) Schottky contacts on AlInGaN quaternary alloy have been investigated in the temperature range of 80–320 K. The zero-bias barrier height (BH) (ΦB0) and ideality factor (n) of them were evaluated using thermionic emission (TE) theory. The ΦB0 and n values calculated from the I-V characteristics show a strong temperature dependence. Such behavior of ΦB0 and n is attributed to Schottky barrier inhomogeneities. Therefore, both the ΦB0 vs n and ΦB0 vs q/2kT plots were drawn to obtain evidence on the Gaussian distribution (GD) of the barrier height at the metal/semiconductor interface. These plots show two different linear parts at low and intermediate temperatures for as-deposited and annealed Schottky contacts. Thus, the mean value of ΦB0 and standard deviation (σ0) was calculated from the linear parts of the ΦB0 vs q/kT plots for both samples. The values of the effective Richardson constant (A*) and mean BH were obtained from the modified Richardson plots which included the effect of barrier inhomogeneity. These values of Richardson constant and barrier height for as-deposited contacts were found to be 19.9 A cm?2 K?2 and 0.59 eV, respectively, at low temperature, but 43.3 A cm?2 K?2 and 1.32 eV, respectively, at intermediate temperatures. These values of Richardson constant and barrier height for annealed contacts were found to be 19.6 A cm?2 K?2 and 0.37 eV, respectively, at low temperature, but 42.9 A cm?2 K?2 and 1.54 eV, respectively, at intermediate temperatures. It is clear that the value of the Richardson constant obtained for as-deposited and annealed samples by using double-GD for intermediate temperatures is close to the theoretical value of AlInGaN (=44.7 A cm?2 K?2). Therefore, I-V-T characteristics for the as-deposited and annealed Schottky contacts in the temperature range of 80–320 K can be successfully explained based on TE theory with double-GD of the BHs.
关键词： AlInGaN,barrier height,Schottky contacts,Gaussian distribution,thermionic emission
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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Statistical Analysis of the Current–Voltage ( <i>I</i> – <i>V</i> ) and Capacitance–Voltage ( <i>C</i> – <i>V</i> ) Characteristics of the Au/Ir/ <i>n</i> -InGaN Schottky Barrier Diodes
摘要： In the present work, 20 Au/Ir/n-InGaN Schottky barrier diodes (SBDs) are fabricated using a electron beam evaporation technique. The Schottky barrier parameters such as ideality factor (n), Schottky barrier height (SBH) ((cid:2)b(cid:3) and donar concentration (Nd (cid:3) values are determined by current–voltage (I–V ) and capacitance–voltage (C–V ) measurements at room temperature. From I–V measurements, the statistical distribution of data gives the mean SBH value of 0.70 eV with a normal deviation of 10 meV and mean ideality factor value of 1.50 with a normal deviation of 0.0478. Two important parameters such as series resistance (RS(cid:3) and shunt resistance (cid:3) are also evaluated from the I–V characteristics. Furthermore, Norde and Cheung’s methods are used to evaluate the SBH, ideality factor and series resistance. The statistical distribution of C–V data gives the mean SBH value of 0.91 eV with a normal deviation of 12 meV and mean donar concentration of 0.71 × 1017 cm?3 with a normal deviation of 0.018 × 1017 cm?3, respectively.
关键词： Series Resistance,Schottky Barrier Height,Ideality Factor
更新于2025-09-09 09:28:46
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Oxide-Polymer Heterojunction Diodes with a Nanoscopic Phase-Separated Insulating Layer
摘要： Organic semiconductor-insulator blend films are widely explored for high-performance electronic devices enabled by unique phase separation and self-assembly phenomena at key device interfaces. Here we report the first demonstration of high-performance hybrid diodes based on p-n junctions formed by a p-type poly(3-hexylthiophene) (P3HT)-poly(methylmethacrylate) (PMMA) blend and n-type indium-gallium-zinc oxide (IGZO). The thin film morphology, microstructure, and vertical phase separation behavior of the P3HT films with varying contents of PMMA are systematically analyzed. Microstructural and charge transport evaluation indicates that the polymer insulator component positively impacts the morphology, molecular orientation, and effective conjugation length of the P3HT films, thereby enhancing the heterojunction performance. Furthermore, the data suggest that PMMA phase segregation creates a continuous nanoscopic interlayer between the P3HT and IGZO layers, playing an important role in enhancing diode performance. Thus, the diode based on an optimal P3HT-PMMA blend exhibits a remarkable 10-fold increase in forward current versus that of a neat P3HT diode, yielding an ideality factor value as low as 2.5, and a moderate effective barrier height with an excellent rectification ratio. These results offer a new approach to simplified manufacturing of low-cost, large-area organic electronics technologies.
关键词： effective barrier height,ideality factor,IGZO,P3HT,hybrid diode,Organic semiconductor/insulator blend
更新于2025-09-09 09:28:46
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AlN passivation effect on Au/GaN Schottky contacts
摘要： Surface passivation effect with an aluminum nitride (AlN) thin film deposited by atomic layer deposition (ALD) on metal/gallium nitride (GaN) junctions were investigated using current–voltage and capacitance–voltage (C–V) measurements. The sample with an AlN layer revealed higher barrier height and lower ideality factor compared to the sample without AlN layer. X-ray photoelectron spectroscopy measurement on bare GaN surface showed the presence of native oxide on the GaN surface. From C–V measurements, it was found that the interface state density was reduced with an AlN layer. Hence, deposition of AlN layer by ALD can be used to improve the interface quality of metal/GaN junction.
关键词： Thin film,Interface state density,Barrier height,Aluminum nitride
更新于2025-09-04 15:30:14