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Electrical contacts to two-dimensional transition-metal dichalcogenides
摘要: Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have attracted enormous interests as the novel channel materials for atomically thin transistors. Despite considerable progress in recent years, the transistor performance is largely limited by the excessive contact resistance at the source/drain interface. In this review, a summary of recent progress on improving electrical contact to TMDC transistors is presented. Several important strategies including topology of contacts, choice of metals and interface engineering are discussed.
关键词: Fin-FET,channel materials,two-dimension
更新于2025-09-23 15:23:52
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Experimental study for the application of different cooling techniques in photovoltaic (PV) panels
摘要: This article contains the experimental investigations of different cooling methods used for photovoltaic (PV) panels. Phase change material (PCM), thermoelectric (TE) and aluminum fins were chosen as the cooling methods. The CaCl2·6H2O is chosen as one of the PCM which is widely used in the cooling of PVs and the other is the PCM with melting temperature above the surface temperature of the PV panel. By using TE material in different numbers (6, 8 and 12) and aluminum fins in different layouts, surface temperatures and output powers of PV panels were compared. It is observed that the PCM which is not chosen appropriately has insulation feature in the PV panel and enhances the temperature of the panel and decreases the output power. When the most successful cooling methods were tested under the same environmental conditions, PV with fin system produced the highest power generation of 47.88 W while PV with PCM and TEM produced the lowest power generation of 44.26 W.
关键词: Thermoelectric module,Photovoltaic,Fin,Cooling,Phase change material
更新于2025-09-23 15:21:01
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Comparative analysis of different cooling fin types for countering LED luminaires' heat problems
摘要: A significant problem with high-power LED luminaires is heat. Aluminum heat sinks have been extensively used as a solution. The most common method for heat sinks that increases surface area uses fins. In the present study, pin- and plate-fins were compared and it was observed that, in equal surface areas, better cooling was achieved by pin-fins. Thus, the study’s concentration narrowed to pin-fins and the results of different pin-fins were compared. Simulations of a sample group were conducted by using different numbers of fins, and the number of fins giving the lowest Tmax value (the highest junction point temperature) was accepted to be optimum for each group; then the optimum values were compared among the different groups. Keeping the base width of fins constant, optimum values were obtained for the same number of fins when the fin height was changed. However, keeping fin height constant, surface areas of optimum values and measured Tmax values were very close to one another other, even if the base width of fins was changed. The results have practical significance in designing high-power LED luminaires.
关键词: LED cooling,fin height,junction point temperature,base width,High-power LED luminaire,plate-fin heat sink,pin-fin heat sink
更新于2025-09-23 15:19:57
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Estimation of the performance limits of a concentrator solar cell coupled with a micro heat sink based on a finite element simulation
摘要: Concentrated photovoltaic (CPV) technology makes use of cheap optical elements to amplify the irradiance and focus it on small-sized solar cells enabling the extraction of higher amounts of electricity. However, increasing the solar concentration raises the temperature of the PV cell which can deter its performance and can also cause its failure. To combat this issue both active and passive cooling mechanisms are utilized for different types of CPV systems. In this study, we determine the limits of passive cooling systems and establish when an active cooling system is needed based on the recommended operating temperature of the solar cell. We investigate the temperature characteristics of the solar cells bonded to three different substrate materials under different solar concentrations. Results showed that cell temperature is linearly dependent on the concentration ratio and ambient temperature independent of the substrate material. Further, the integration of a micro-finned heatsink results in higher heat dissipation by 25.32%, 23.13%, and 22.24% in comparison with a flat plate heatsink for Direct Bonded Copper (DBC), Insulated Metal Substrate (IMS), and Silicon Wafer (Si wafer) substrates respectively. The low thermal resistance of the IMS substrate compared to the DBC and the Si wafer substrates result in the best thermal performance in terms of maintaining the cell temperature < 80 °C and allowing a wider range of high concentration ratio.
关键词: Concentration Ratio,Passive cooling,micro fin heat-sink,finite element,Concentrating Photovoltaic,flat-plate heat-sink
更新于2025-09-23 15:19:57
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Scalable fabrication of a complementary logic inverter based on MoS <sub/>2</sub> fin-shaped field effect transistors
摘要: Integration of high performance n-type and p-type field-effect transistors with complementary device operation in the same kind of layered materials is highly desirable for pursuing low power and flexible next-generation electronics. In this work, we have shown a well-mannered growth of MoS2 on a fin-shaped oxide structure and integration of both n-type and p-type MoS2 by using a traditional implantation technique. With the advance of the fin-shaped structure, the maxima and the effective ON current density for the MoS2 fin-shaped field-effect transistors are respectively obtained to be about 50 μA μm?1 (normalized by the circumference of the fin) and around 500 μA μm?1 (only normalized by the fin size), while its ON/OFF ratio is more than 10? with low OFF current of a few pA. Based on our n-type and p-type MoS2 fin-shaped field-effect transistors, the complementary MoS2 inverter with a high DC voltage gain of more than 20 is acquired. Our results provide evidence for complementary 2D material operation in the same materials, a promising avenue for the development of high performance and high-density complementary 2D electronic devices.
关键词: ion implantation,2D materials,fin-shaped field-effect transistors,MoS2,complementary logic inverter
更新于2025-09-19 17:15:36
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Improving Performance of a Photovoltaic Panel by Pin Fins: A Theoretical Analysis
摘要: As efficiency of PV modules decreases with temperature rise, cooling methods can increase the power output and efficiency. One of the strategies for this purpose is passive cooling by implementing fins to the backside of a module. In the present study, annual energy output of a 50 W panel is analytically calculated in two unfinned and pin-finned cases based on hourly meteorological data for Shiraz, Iran. The results show that with the installation of 2-cm, 4-cm and 6-cm aluminum pin fins with finned-to-total-backside-area ratios of 0.17, 0.27 and 0.55, the power output increases by 1.24–4.16%, compared to the unfinned case. This increase is equivalent to 1.04–3.50 kWh more electrical energy production during a year.
关键词: Fin,Photovoltaic panels,Passive cooling,Solar energy
更新于2025-09-11 14:15:04