纳米WO_3基材料的研究进展

WO3是一种优良的n型无机半导体材料,因其独特的物理化学性质及在光致变色、气敏、光催化降解等领域的广泛应用,得到了人们的普遍关注。结合近年来国内外相关文献,综述了WO3的制备方法及掺杂改性的研究进展,比较了几种常用制备方法的优缺点,探讨了掺杂的种类以及不同掺杂对纳米WO3材料在电致变色、气敏、光学性质及其他方面的影响。最后,对纳米WO3材料的发展趋势和纳米WO3材料掺杂制备优化的前景做出了展望和分析。     

Influence of ITO,Graphene Thickness and Electrodes Buried Depth on LED Thermal-Electrical Characteristics Using Numerical Simulation

Finite elements methods are used to investigate the thermal-electrical characteristics of gallium-nitride （GaN） light-emitting diodes （LEDs） with different transparent conductive layers （TCLs） and buried depths of electrodes, where the transparent conductive layers include indium tin oxide （ITO）, graphene （Gr） and the combination of them （ITO/Gr）. The optimal material parameters and the precision and accuracy of the simulation model are validated. Moreover, the parameters＇ sensitivity analysis is carried out as well. The results indicate that the LED with the TCL of a lO0-nm ITO or 4-1ayer Gr has a good thermal-electrical performance from the viewpoint of the maximum temperature and the current density deviation of multiple quantum well （MQW）, where the maximum temperature occurs at the n-Pad rather than p-Pad. The compound TCL with a 20-nm ITO and 3- layer Gr reaches a thermal-electrical performance better than that of a lO0-nm ITO or 4-layer Gr. Moreover, their maximum temperatures decrease about -0.43% and 1.21%, and the current density uniformities increase up to -6.09% and 17.41%, respectively. Furthermore, when the electrode buried depth is 0.51 μm, the thermal-electrical performance of the GaN LEDs can be further improved.