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We study the two samples of AlInGaN,i.e.,1-μm Gan grown at 1030℃ on the buffer and followed by a 0.6μm-thick epilayer of AlInGaN under the low pressure of 76 Torr and the AlInGaN layer deposited diectly on the buffer layer without the high-temperature GaN layer,by temperature-dependent photoluminescence(PL) spectroscopy and picosecond time-resolved photoluminescence(TRPL) spectroscopy.The TRPL signals of both the samples were fitted well as a stretched exponential decay at all temperatures,indicating significant disorder in the material.We attribute the disorder to nanoscale quantum dots or discs of high indium concentration.Temperature dependence of dispersive exponent β shows that the stretched exponential decay of the two samples comes from dfferent mechanisms.The different depths of the localization potential account for the difference,which is illustrated by the results of temperature dependence of radiative recombination lifetime and PL peak energy. 相似文献
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在不同的生长温度和载气的条件下,采用低压金属有机物气相外延方法生长了系列的InAlGaN薄膜,通过能量色散谱(EDS),高分辨X射线衍射(HRXRD)和光致发光谱(PL)对样品进行表征与分析,研究了生长工艺对InAlGaN外延层结构和光学性能的影响.发现当以氮气做载气时,样品的发光很弱并且在550nm附近存在一个很宽的深能级发光峰;当采用氮气和氢气的混合气做载气时,样品中的深能级发光峰消失且发光强度明显提高.以混合气做载气,InAlGaN薄膜中铟的组分随生长温度的升高而降低,而薄膜的结构和光学性能却提高.结合PL和HRXRD的测试结果得到了较佳的生长参数:即载气为氢气和氮气的混合气以及生长温度在850℃到870℃. 相似文献
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研究AlInGaN材料的生长特性及其光学性质.通过对不同生长温度生长的三个AlInGaN样品的 测量,发现In的掺入量随着生长温度的降低而增加,而Al的掺入几乎没什么变化;在较低温 度下生长的材料具有较好的材料质量与光学特性,其原因直接与In组分的掺入有关,In组分 的掺入可以减少材料的缺陷,改善材料的质量.同时,用时间分辨光谱研究了AlInGaN材料的 发光机理,发现其发光强度随时间变化(荧光衰退寿命)不是指数衰减,而是一种伸展的指 数衰减.通过对这种伸展的指数衰减特性的研究,发现AlInGaN发光来自
关键词:
AlInGaN
MOCVD
局域激子
量子点 相似文献
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在不同的生长温度和载气的条件下,采用低压金属有机物气相外延方法生长了系列的InAlGaN薄膜,通过能量色散谱(EDS),高分辨X射线衍射(mixRD)和光致发光谱(PL)对样品进行表征与分析,研究了生长工艺对InAlGaN外延层结构和光学性能的影响。发现当以氮气做载气时,样品的发光很弱并且在550nto附近存在一个很宽的深能级发光峰;当采用氮气和氢气的混合气做载气时,样品中的深能级发光峰消失且发光强度明显提高。以混合气做载气,InAlGaN薄膜中铟的组分随生长温度的升高而降低,而薄膜的结构和光学性能却提高。结合PL和HRXRD的测试结果得到了较佳的生长参数:即载气为氢气和氮气的混合气以及生长温度在850℃到870℃。 相似文献
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InAlN/GaN heterojunction structures are grown on two-inch c-face(0001) sapphire substrates by metalorganic chemical vapour deposition. AlN and AlGaN interlayers are intentionally inserted into the structure to improve the electrical properties. The lowest sheet resistance of 359 Ω/sq and the highest room-temperature two-dimensional electron gas (2DEG) mobility of 1051 cm2 V-1s-1 is obtained in the structure with AlN thickness of 1.3 nm. The structure with AlN thickness of 2 nm exhibits the highest 2DEG concentration of 1.84×1013 cm-2. The sample with an AlGaN interlayer gives a smoother surface morphology compared to the one using an AlN interlayer, indicating potential applications of this technique in device fabrication. 相似文献
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We report on the fabrication and characterization of phototransistors based on AIGaN/GaN heterostructure grown over 6H-SiC substrates. The device has two functions: as a high electron mobility transistor (HEMT) and an ultraviolet photodetector at the same time. As an HEMT, its maximum transconductance is 170mS/ram, while the minimum cutoff frequency fT and the maximum oscillation frequency fm are 19 and 35 GHz, respectively. As a photodetector, the device is visible blind, with an ultraviolet/green contrast of three orders of magnitude, and a responsivity as high as 1700 A/W at the wavelength of 362nm. 相似文献
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利用低压MOCVD技术在蓝宝石衬底上生长了AlGaN/GaN二维电子气(2DEG)材料,在GaN生长中插入一层低温GaN,并研究了低温GaN插入层对二维电子气输运特性的影响.使用原子力显微镜(AFM)和非接触霍尔测试仪测量了材料的表面形貌和电学特性,发现低温GaN插入层可以改善材料表面平整度并使AlGaN/GaN 2DEG的电子迁移率有明显提高,GaN插入层温度为860℃的样品在室温下2DEG的电子迁移率达到2110 cm2/V·s. 相似文献
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