Papers by Keyword: Sheet Resistance

Abstract: Accurate characterization of low-resistance ohmic contacts on 4H-SiC is crucial for devicedevelopment, but is complicated by the limitations of the standard Transfer Length Method (TLM).TLM test structures are widely used for extracting the specific contact resistivity (ρC) between metaland semiconductor layers, as well as the sheet resistance of doped layers. The contact formation pro-cess itself, particularly the annealing step, modifies the SiC layer under the contact. This results in asheet resistance below the contact (RSK) that deviates from the sheet resistance of interest between thecontacts (RSH), which invalidates a key assumption of the standard TLM evaluation of a constant RSHthroughout the whole TLM test structure. This study uses 2D TCAD simulation of TLM test structuresto investigate the influence of the contact length L, while using an advanced evaluation method forextracting ρC with the help of a third contact. Consequently, it is necessary to measure the contactend resistance RCE, which is derived from the potential at the end of the TLM contact. The findingsprovide a deeper understanding of the TLM technique’s robustness and offer valuable guidelines foroptimizing TLM test structures to ensure accurate characterization of ohmic contacts on 4H-SiC.

Abstract: The study investigated the effect of iodine-doped pentacene film as a buffer layer in an organic light-emitting diode (OLED). In this study, an ITO (indium tin oxide)-based sample is used as a reference device for comparative purposes. In OLED devices, the buffer layers were deposited using the doping of iodine vapor with the pentacene materials under proper conditions. The thermal treatment of the doped pentacene film results in increasing the conductivity of the buffer layer. Surface morphology for the bilayer anode was carried out by FESEM (Field Emission Scanning Electron Microscope) analysis. In our work, maximum luminance of 2345 cd/m² and current efficiency of 5.4 cd/A are obtained, along with more stability performance under annealing treatment in the device structure of FTO/iodine-doped pentacene (30 nm)/TPD [N, N′-Bis(3-methyl phenyl)-N, N′-diphenylbenzidine] (44 nm)/Alq3 [Tris(8-hydroxyquinoline)aluminum(III)] (52 nm)/LiF (lithium fluoride) (5 nm)/Al (aluminum) (110 nm).

Abstract: The determination of the dependencies of the electrical resistivity of the thin film to temperature is of great importance both for understanding the conduction mechanism and for numerous technical applications of these films. In this work, to characterize, the electrical properties of thin films, a GM cryocooler-based automatic board temperature range electrical properties measurement system has been constructed. The system can measure multiple samples simultaneously. The cooling process was simulated using the time-discrete differencing to validate the optimized device design parameters and minimize heat losses. Furthermore, the temperature-dependent sheet resistance results were compared with the results from the physical property measurement system.

Abstract: The results of the first experiments for achieving the thermal equilibrium during 1300 °C annealing of 1×10²⁰ cm^-3 ion implanted Al⁺ in 3C-SiC are shown. X-ray diffraction, through reciprocal space maps and 2Θ scans, characterizes the 3C-SiC lattice recovery. The achievement of a ohmic behavior of Ni/Al/Ti alloy indicates the onset of a measurable electrical activation of the Al implanted layer. The Al electrical activation is qualified through the implanted layer sheet resistance.

Abstract: High aspect ratio silver nanowires (AgNWs) with an average length of 40 μm and average diameter of 88 nm were successfully synthesized using waste ethylene glycol as solvent and reducing agent. Silver nanowires with an average length and diameter of 32 μm and 122 nm, were produced after the third cycle of being reused. A transparent conducting film with a sheet resistance of 69 Ω/sq and optical transmittance of 91% was fabricated by Meyer rod coating an ink formulation of AgNWs dispersed in hydroxyethyl celullose (HEC)/methanol/deionized water. The low resistance of the AgNW networks was maintained even after 1000 bending cycles due to HEC acting as binder for the nanowires. The AgNWHEC transparent conductive electrode performed better than bare AgNWs and indium tin oxide (ITO) on polyethylene terephthalate (PET) substrate after several bending cycles. The AgNW-HEC electrode also showed excellent stability against corrosion.

Abstract: In this paper, graphene nanosuspension was spray deposited using electrohydrodynamic atomization (EHDA) technique, and the polydimethylsiloxane (PDMS) was used as the substrate during the EHDA process. The effect of the PDMS substrate before and after oxygen plasma treatment on the characteristics of EHDA was examined. A cone-jet mode of the EHDA of graphene nanosuspension was obtained using the oxygen plasma treated PDMS substrate. In addition graphene films were deposited on the oxygen plasma treated PDMS at different working distances. The lowest sheet resistance of the graphene films is 127Ω·sq^-1. Furthermore, graphene lines at the range of 30μm-170μm were fabricated using the template assisted EHDA deposition method.

Abstract: Multilayer structure with SnO₂/Ag//SnO₂ was prepared on glass substrates by sequential using RF/DC magnetron sputtering at room temperature. In order to estimate and compare with the experimental results in advance, EMP (Essential Macleod Program) simulation program was adopted. EMP simulation results suggested that the multilayered thin film of SnO₂ (30 nm)/Ag (10 nm)/SnO₂ (30 nm) exhibited the highest visible transmittance of 88.8 % at 550 nm, whereas experimentally measured transmittance showed 85.5 %, somewhat lower than simulation data. Even though most of films exhibit transmittance of about 88 % at 550 nm wavelength, there are some distinct differences between the experimental and simulated results. Sheet resistance (Rs) were almost constant and the lowest Rs value about 9.51 Ω/sq was acquired at the multi layers with the structure of SnO₂ (30nm)/Ag (10nm)/SnO₂ (30nm). However, the resistivity of the SnO₂/Ag/SnO₂ multi layer film increased systematically with increasing thickness of SnO₂ layer from 30 to 50 nm. SnO₂/Ag/SnO₂ multilayer with 50 nm of SnO₂ thickness resulted in a decrease of Φ_TC due to decrease of transmittance. The highest Φ_TC value of SnO₂/Ag/SnO₂ film was obtained at a SnO₂ thickness of 35 nm.

Abstract: W-Ti thin films with different Ti contents were prepared by dc magnetron sputtering on silicon substrates of p-type (100) orientation, and the pure W and pure Ti thin films with the same thick were also prepared for comparison. The microstructure and properties of W-Ti thin film were characterized by XRD, SEM, AFM, microhardness tester and four-point probe method. The results show that the thin films exhibited a polycrystalline structure in the form of columnar grains, and only b.c.c. W phase could be registered in the films, and with the increase of Ti content, the solid solution of W-Ti was found. Compared to pure W film, the microhardness of W-Ti films decreased with the increasing of Ti content, while the sheet resistance rises with the increasing of Ti content. The microhardness of W-Ti thin films was higher than pure Ti thin films, and the sheet resistance was lower than pure Ti thin films.

Abstract: In this paper, APPJ (Atmospheric pressure Pules arc Plasma Jet) is used to generate a DC pulse source depositing GZO thin film under atmospheric pressure. Thus, no vacuum chamber needed leads to the cost downward. With scanning operation, makes single unit area into large size area. Several key process parameters have been studied, including the power supply voltage, DC pulse, the length of the nozzle extended head, and depositing gap to understand their relationship with the film quality and atmospheric plasma state.In this study, with adjusting DC pulse, the pulse frequency is found to have a great impact on the plasma state and the film quality. When the pulse frequency is near 25 kHz, lower sheet resistance can be retained. Besides, adjusting T_off time, the plasma and thin film quality are influenced more than T_on time. By changing the power supply voltage, the secondary-side voltage decreases with increasing of the instantaneous current; moreover, the plasma will become more intense.

Abstract: The article analyses the principle of square four probe measurement technology. The principle of the probe vacillated at testing a large silicon wafer is analyzed, and interference can be avoided while measuring and analyzing the impact on square four probe measurement by probe vacillate. The influence of probe wavering using square four probe method for the equipment designed by authors is analyzed with detailed data, and calculated error of the probe wander. Probe positions of maximum error produced are found, so ensuring testing accuracy schemes are proposed at last.