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为了研究AlGaN量子阱层和垒层中Al组分不同对AlGaN基深紫外发光二极管(LED)光电性能的影响,本文利用MOCVD生长、光刻和干法刻蚀工艺制备了AlGaN量子阱层和垒层具有不同Al组分的270/290/330nm深紫外LED,通过实验和数值模拟计算方法发现,量子阱层和垒层中具有低Al组分紫外LED的AlGaN材料具有较低的位错密度、较高的光输出功率和外量子效率。通过电流-电压(I-V)曲线拟合出的较大的理想因子(3.5)和能带结构图表明,AlGaN深紫外LED的电流产生是隧穿机制占据主导作用,这是因为高Al组分AlGaN量子阱中强极化场造成了有源层区域较大的能带弯曲和电势降。 相似文献
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GaN nanorods in a large scale have been synthesized on Si (111) substrates by ammoniating Ga2O3/Mg films under flowing ammonia atmosphere at the temperature of 1000℃ for 15 min. The as-synthesized GaN nanorods are characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and highresolution transmission electron microscopy. The results demonstrate that these straight nanorods are hexagonal wurtzite GaN single crystals in diameters ranging from 200 nm to 600 nm. 相似文献
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为了制备单芯片无荧光粉白光InGaN/GaN多量子阱发光结构,利用选择性外延生长法在SiO2条纹掩膜板上生长出具有梯形形貌的GaN微面结构,并在该GaN微面结构上生长InGaN/GaN多量子阱结构,最终在单芯片上获得了双波长发光.结果表明:梯形GaN微面由(0001)和(11-22)面组成,两者的表面能和极性不同,并且在InGaN/GaN多量子阱生长过程中,In原子和Ga原子迁移速率不同,从而使得(0001)和(11-22)面上的多量子阱具有不同的发光波长;该性质可以使(11-22)面的微面量子阱发出蓝光(峰值波长为420nm),而(0001)面的量子阱发出黄光(峰值波长为525nm),最终形成双波长的复合白光外延结构. 相似文献
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Syringe-shaped GaN nanorods are synthesized on Si(111) substrates by annealing sputtered Ga2O3/BN films under flowing ammonia at temperature of 950℃. Most of the nanorods consist of a main rod and a top needle, looking like a syringe. X-ray diffraction and selected-area electron diffraction confirm that the syringe-shaped nanorods are hexagonal wurtzite GaN. Scanning electron microscopy and high-resolution transmission electron microscopy reveal that these nanorods are as long as several micrometres, with diameters ranging from 100 to 300nm. In addition to the BN intermediate layer, the proper annealing temperature has been demonstrated to be a crucial factor for the growth of syringe-shaped nanorods by this method. 相似文献
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利用Pd催化合成单晶GaN纳米线的光学特性(英文) 总被引:1,自引:0,他引:1
基于金属元素钯具有的催化特性,采用射频磁控溅射方法,在Si(111)衬底上沉积Pd:Ga2O3薄膜,然后在950℃下对薄膜进行氨化,制备出大量GaN纳米线.采用扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等技术手段对样品的结构、形貌和成分进行分析.结果表明,制备的样品为具有六方纤锌矿结构的单晶GaN纳米线,直径在20-60nm范围内,长度为几十微米,表面光滑无杂质,结晶质量较高.用光致发光光谱对样品的发光特性进行测试,分别在361.1、388.6和426.3nm处出现三个发光峰,且与GaN体材料相比近带边紫外发光峰发生了较弱的蓝移.对GaN纳米线的生长机制也进行了简单的讨论. 相似文献
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采用简单的碳热蒸发法在硅衬底上制备了四足棒球棒状ZnO纳/微米材料,结合光致发光谱(PL)、阴极射线发光谱(CL)、XRD谱、SEM以及TEM等分析了该材料的结构和发光特性.结果表明,制备的单晶ZnO纳/微米材料具有纤锌矿结构,并且沿着c轴方向择优生长;每个纳/微米结构有四个足,每个足的直径约为0.2~1.5 μm,长度约为3 ~10 μm;室温光致发光谱中包含一个384 nm附近的较弱的近紫外发光峰和一个519 nm附近的较强的绿色发光峰;在单个四足状ZnO纳/微米结构不同位置获得的阴极射线发光谱也被用于对比分析.最后讨论了Ni缓冲层的作用及ZnO四足棒球棒状的生长机理. 相似文献
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We report a new method for large-scale production of GaMnN nanobars, by ammoniating Ga2O3 films doped with Mn under flowing ammonia atmosphere at 1000oC. The Mn-doped GaN sword-like nanobars are a single-crystal hexagonal structure, containing Mn up to 5.43 atom%. Thickness is about 100 nm and with a width of 200-400 nm. The nanobars are characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and photoluminescence. The GaN nanobars show two emission bands with a well-defined PL peak at 388 nm and 409 nm respectively. The large distinct redshift (409 nm) are comparable to pure GaN(370 nm) at room temperature. The red-shift photoluminescence is due to Mn doping. The growth mechanism of crystalline GaN nanobars is discussed briefly. 相似文献