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Hole carrier mediated magnetization in Cu-doped GaN is investigated by using the first-principles calculations.By studying the sp-d interaction and the direct exchange interaction among the dopants,we obtain an equation to determine the spontaneous magnetization as a function of the Cu dopant concentration and the hole carrier density.It is demonstrated that nonmagnetic Cu doped GaN can be of room-temperature ferromagnetism.The system’s Curie temperature Tc can reach about 345 K with Cu concentration of 1.0% and hole carrier density of 5.0×1019 cm-3.The results are in good agreement with experimental observations and indicate that ferromagnetism in this systems is tunable by controlling the Cu concentration and the hole carrier density. 相似文献
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在介电连续模型和单轴模型的框架下,采用雷-丁平衡方程理论,考虑量子阱中界面光学声子模和局域体光学声子模的影响,分别计算了纤锌矿型和闪锌矿型AlN/GaN量子阱中电子平行于异质结界面方向的迁移率,给出迁移率随阱宽的变化关系,并讨论了结构各向异性效应对电子迁移率的影响. 相似文献
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提出了一种利用正向电压下的导纳—电压(A—V)特性检测半导体二极管的非破坏性新方法,并给出了它的一般分析.利用这种方法,可以判断一个二极管有无界面层存在,并测量在不同正向电压下串联电阻、结电容、结电压、理想化因子和界面层阻抗的数值.用A—V方法研究了采用不同的欧姆接触的Ni/n—GaN肖特基二极管,观察到肖特基二极管的负电容现象,并确认是一种结的效应.研究还发现,无论缺乏n^ 层还是缺乏适当的退火都能够导致界面层的形成,界面层应被看作具有非线性电阻和电容的层状结构. 相似文献
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为了得到具有较好紫外发射特性的ZnO纳米杆阵列,以氢气腐蚀过的GaN薄膜为衬底,在较低的温度(105°C)下采用水浴法制备图形化ZnO纳米杆阵列。对制备的样品进行结构和形貌表征,并通过对比实验研究氢气腐蚀处理的影响。结果表明,氢气腐蚀过的GaN薄膜衬底,有利于形成致密、均匀、定向排列的ZnO六边形图案,符合螺旋位错驱使的生长机制。 相似文献
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由于GaN基量子点具有较强的量子效应,有望获得比其他量子阱器件更优异的性能。目前GaN基量子点的制备及其光学特性已经成为Ⅲ-Ⅴ族半导体器件研究的热点。探讨了GaN基量子点的生长及其结构特性,重点研究了GaN基量子点的S-K生长模式及其影响量子点生长的因素,并讨论了GaN基量子点的光致发光特性及其影响因素。 相似文献
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杂质对柱形量子点系统束缚能的影响 总被引:1,自引:0,他引:1
在有效质量近似和变分原理的基础上,考虑内建电场(BEF)效应和量子点的三维约束效应.研究了纤锌矿结构的GaN/AlxGa1xN单量子点中杂质体系的基态能量与杂质电荷的关系,讨论了杂质电子的束缚能随量子点的主要结构参数(量子点高度L和量子点半径R)以及杂质在量子点中不同位置的变化规律,并研究了考虑量子点内外电子有效质量失配对杂质电子束缚能的影响. 相似文献
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Yi-jung LIU Chien-chang HUANG Tai-you CHEN Chi-shiang HSU Shiou-ying CHENG Kun-wei LIN Jian-kai LIOU Wen-chau LIU 《自然科学进展(英文版)》2010,20(1):70-75
An InGaN/GaN multiple-quantum-well (MQW) light-emitting diode (LED) with a ten-period i (undoped) -InGaN/p (Mg doped) -GaN (2.5 nm/5.0 nm) superlattice (SL) structure, was fabricated. This SL structure that can be regarded as a confinemen t layer of holes to enhance the hole injection efficiency is inse rted between MQW and p-GaN layers. The studied LED device exhibits better current spreading performance and an improved quality, compared with a conventional one without SL structure. Due to the
reduced contact resistance as well as more uniformity of carrier s injection, the operation voltage at 20 mA is decreased from 3.32 to 3.14 V. A remarkably reduced reverse-biased leakage current (10-7?10-9 A) and higher endurance of the reverse current pulse are found. The measured output power and external quantum efficiency (EQE) of the studied LED are 13.6 mW and 24.8%, respectively. In addition, significant enhancement of 25.4% in output power as well as increment of 5% in EQE for the studied devices is observed, as the studied devices show s uperior current spreading ability and reduction in dislocations offered by the SL structure. 相似文献
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近年来,后石墨烯时代许多新型二维材料表现出优异的物理化学性能,同时以二维半导体材料为基础构建的二维范德华异质结复合材料为改善光催化剂性能开辟了新的研究方向。二维范德华异质结光催化剂可以增强对可见光的吸收和降低电子和空穴的复合,极大提升光催化性能。氮化镓(gallium nitride,GaN)材料具有禁带宽度大、电子漂移速度快、抗腐蚀性强和耐高温等优点,这为其作为半导体光催化剂提供了可能。介绍了光催化剂材料筛选和二维GaN基范德华异质结研究进展等,通过第一性原理密度泛函理论对二维GaN基异质结体系的光催化性质进行研究分析。 相似文献
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