共查询到17条相似文献,搜索用时 62 毫秒
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GaN薄膜的蓝光和红光发射机理研究 总被引:3,自引:3,他引:3
由于生长工艺的不完善,非掺杂GaN薄膜中通常存在未知的杂质和缺陷,产生与这些未知杂质和缺陷能级相关的发光。报道了非掺杂GaN薄膜的692nm红色发光.并研究了非掺杂GaN薄膜的蓝、红色发光的发射机理;利用作者提出的吸收归一化光致发光激发光谱,直接测量出了非掺杂GaN薄膜的蓝、红色发光的初始态能级,确定蓝色发光为施主-价带跃迁复合,而红色发光为施主-受主跃迁复合;给出了黄、蓝、红光的发射模型。所取得的结果对于确定未知杂质和缺陷的种类具有重要的参考价值。 相似文献
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分子束外延高Mg掺杂GaN的发光特性 总被引:2,自引:0,他引:2
采用分子束外延技术在蓝宝石衬底上制备Mg掺杂的立方相p-GaN,并对其不同温度下的光致发光光谱进行了研究.实验观察到高Mg掺杂GaN中施主受主对发光的反常温度行为.理论分析表明,高Mg掺杂GaN中施主受主对的发光受到陷阱与受主间竞争俘获非平衡空穴过程和空穴隧穿输运过程的影响. 相似文献
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采用MOCVD技术在图形化硅衬底上生长了InGaN/GaN多量子阱黄光LED外延材料,研究了不同的量子阱生长气压对黄光LED光电性能的影响。使用高分辨率X射线衍射仪(HRXRD)和荧光显微镜(FL)对晶体质量进行了表征,使用电致发光系统积分球测试对光电性能进行了表征。结果表明:随着气压升高,In的并入量略有降低且均匀性更好,量子阱中的点缺陷数目降低,但是阱垒间界面质量有所下降。在实验选取的4个气压4,6.65,10,13.3 kPa下,外量子效率最大值随着量子阱生长气压的上升而显著升高,分别为16.60%、23.07%、26.40%、27.66%,但是13.3 kPa下生长的样品在大电流下EQE随电流droop效应有所加剧,在20 A·cm-2的工作电流下,样品A、B、C、D的EQE分别为16.60%、19.77%、20.03%、19.45%,10 kPa下生长的量子阱的整体光电性能最好。 相似文献
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This paper reports that the yellow luminescence intensity of N-polar GaN Epi-layers is much lower than that of Ga-polar ones due to the inverse polarity,and reduces drastically in the N-polar unintentionally-doped GaN after etching in KOH solution.The ratio of yellow luminescence intensity to band-edge emission intensity decreases sharply with the etching time.The full width at half maximum of x-ray diffraction of(10-12) plane falls sharply after etching,and the surface morphology characterized by scanning electron microscope shows a rough surface that changes with the etching time.The mechanism for the generation of the yellow luminescence are explained in details. 相似文献
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M. Sabooni M. Esmaeili H. Haratizadeh B. Monemar P. Paskov S. Kamiyama M. Iwaya H. Amano I. Akasaki 《Opto-Electronics Review》2007,15(3):163-167
We report results from optical spectroscopy such as photoluminescence (PL) and time resolved photo-luminescence (TRPL) techniques
from different well width MOCVD grown GaN/Al0.07Ga0.93N MQW samples. There is evidence of localization at low temperature in all samples. The decay time of all samples becomes
non-exponential when the detection energy is increased with respect to the peak of the emission. Localization of carriers
(excitons) is demonstrated by the “S-shape” dependences of the PL peak energies on the temperature. The time-resolved PL spectra
of the 3-nm well multi quantum wells reveal that the spectral peak position shifts toward lower energies as the decay time
increases and becomes red-shifted at longer decay times. There is a gradient in the PL decay time across the emission peak
profile, so that the PL process at low temperatures is a free electron-localized hole transition. 相似文献
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Luminescence of a GaN grain with a nonpolar and semipolar plane in relation to microstructural characterization 下载免费PDF全文
We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask.Transmission electron microscopy,scanning electron microscopy,and Raman spectroscopy are used to reveal the effect of SiN on the overgrown a-plane GaN growth.The SiN layer effectively terminates the propagation of the threading dislocation and basal plane stacking faults during a-plane GaN regrowth through the interlayer,resulting in the window region shrinking from a rectangle to a "black hole".Furthermore,strong yellow luminescence(YL) in the nonpolar plane and very weak YL in the semipolar plane on the GaN grain is revealed by cathodoluminescence,suggesting that C-involved defects are responsible for the YL. 相似文献
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Limin Zhang Xiaodong Zhang Wei You Zhen Yang WenXiu Wang Qing Ge Zhengmin Liu 《Central European Journal of Physics》2008,6(2):283-288
The effects of Si, O, C and N ion implantation with different implantation doses on yellow luminescence (YL) of GaN have been
investigated. The as-grown GaN samples used in the work were of unintentional doped n-type, and the photoluminescence (PL)
spectra of samples had strong YL. The experimental results showed that YL of ion implanted samples exhibited marked reductions
compared to samples with no implantation, while the near band edge (NBE) emissions were reduced to a lesser extent. The deep-level
centers associated with YL may be produced in GaN films by O and C ion implantation, and identities of these deep-level centers
were analyzed. It was also found that the dose dependence of YL was analogous with the one of the intensity ratios of YL to
the near band edge (NBE) emission (I
YL
/I
NBE
) for ion implanted samples. The possible reason for this comparability has been proposed.
相似文献
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Point defect determination by photoluminescence and capacitance-voltage characterization in a GaN terahertz Gunn diode 下载免费PDF全文
Photoluminescence (PL) measurement is used to study the point defect distribution in a GaN terahertz Gunn diode, which is able to the degrade high-field transport characteristic during further device operation. PL, secondary ion mass spectroscopy (SIMS), transmission electron microscope (TEM), and capacitance-voltage (C-V) measurements are used to discuss the origin of point defects responsible for the yellow luminescence in structures. The point defect densities of about 1011 cm-2 in structures are extracted by analysis of C-V characterization. After thermal annealing treatment, diminishments of point defect densities in structures are efficiently demonstrated by PL and C-V results. 相似文献
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Intrinsic relationship between photoluminescence and electrical characteristics in modulation Fe-doped AlGaN/GaN HEMTs 下载免费PDF全文
The photoluminescence(PL) and electrical properties of Al GaN/GaN high electron mobility transistors(HEMTs) with different Fe doping concentrations in the GaN buffer layers were studied. It was found that, at low Fe doping concentrations,the introduction of Fe atoms can result in a downward shift of the Fermi level in the GaN buffer layer, since the Fe atoms substitute Ga and introduce an Fe_(Ga)~(3+/2+) acceptor level. This results in a decrease in the yellow luminescence(YL) emission intensity accompanied by the appearance of an infrared(IR) emission, and a decrease in the off-state buffer leakage current(BLC). However, a further increase in the Fe doping concentration will conversely result in the upward shift of the Fermi level due to the incorporation of O donors under the large flow rate of the Fe source. This results in an increased YL emission intensity accompanied by a decrease in the IR emission intensity, and an increase in the BLC. The intrinsic relationship between the PL and BLC characteristics is expected to provide a simple and effective method to understand the variation of the electrical characteristic in the modulation Fe-doped HEMTs by optical measurements. 相似文献
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用时间分辨光谱学方法研究低压有机金属化学汽相沉积生长的GaN中自由,束缚激子(BX)的跃迁,讨论了这些跃迁的光致发光谱,复合寿命及其与温度的关系,给出了中性施主束缚激子和自由激子(FX)的辐射复合寿命分别为0.12ns和0.4ns。 相似文献