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1.
Nonpolar a-plane light-emitting diode with an in-situ SiNx interlayer on r-plane sapphire grown by metal-organic chemical vapour deposition 下载免费PDF全文
We report on the growth and fabrication of nonpolar a-plane light emitting diodes with an in-situ SiNx interlayer grown between the undoped a-plane GaN buffer and Si-doped GaN layer. X-ray diffraction shows that the crystalline quality of the GaN buffer layer is greatly improved with the introduction of the SiNx interlayer. The electrical properties are also improved. For example, electron mobility and sheet resistance are reduced from high resistance to 31.6 cm2/(V·s) and 460 Ω/口 respectively. Owing to the significant effect of the SiNx interlayer, a-plane LEDs are realized. Electroluminescence of a nonpolar a-plane light-emitting diode with a wavelength of 488nm is demonstrated. The emission peak remains constant when the injection current increases to over 20 mA. 相似文献
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Optical and Electronic Properties of InGaN/GaN Multi—Quantum—Wells Near—Ultraviolet Lighting—Emitting—Diodes Grown by Low—Pressure Metalorganic Vapour Phase Epitaxy 下载免费PDF全文
The near-ultraviolet lighting-emitting-diodes (UV-LEDs) with the InGaN/GaN multi-quantum-well (MQW) structure were grown by low-pressure metalorganic vapour phase epitaxy. The double crystal x-ray diffraction revealed a distinct second-order satellite peak. The near-ultraviolet InGaN/GaN MQW LEDs have been successfully fabricated to emit at 401.2nm with narrow FWHM of 14.3nm and the forward voltage of 3.6 V at 20 mA injection current at room temperature. With increasing forward current from l 0 mA to 50 mA, the redshift of the peak wavelength was observed due to the band-gap narrowing caused by heat generation. 相似文献
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本文利用Fourier空间的比较原理研究一类拟线性抛物方程解的Blow-up问题,并给出了其解在有限时刻Blow-up的条件。 相似文献
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本文利用Fourier空间的比较原理研究一类拟线性拟抛物方程解的Blow-up问题,并给出了其解在有限时刻Blow-up的条件。 相似文献
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一类三阶拟线性发展方程的整体解 总被引:1,自引:0,他引:1
杨志坚 《高校应用数学学报(A辑)》1998,13(1):31-38
本文研究一类三阶拟线性发展方程utt-Δut+ut=ni=1xiσi(uxi),(x,t)∈Ω×(0,T)的初边值问题,其中ΩRn(n≥1)为一有界域.证明了只要σi(s)∈C1,σ′i(s)(i=1,…,n)有界并且初始函数满足一定的条件,则上述问题存在唯一的整体弱解. 相似文献
6.
杨志坚 《应用泛函分析学报》2002,4(4):350-356
研究一类非线性发展方程初边值问题整体弱解的存在性,渐近性和解的爆破问题,证明在关于非线性项的不同条件下,上述初边值问题分别在大初值和小初始能量的情况下存在整体弱解,并且讨论了弱解的渐近性。还证明:在相反的条件下,上述弱解在有限时刻爆破,并且给出了一个实例。 相似文献
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The Mg-delta-doped GaN structure has been grown by low-pressure metalorganic chemical vapour deposition.The Hall-effect measurements reveal that the electrical properties are enhanced. The hole concentration is enhanced twice and hole mobility is enhanced three times by Mg-delta doping. Both the etch pit density data and the x-ray diffraction data demonstrate that Mg-delta doping can reduce the threading dislocation density of p-type GaN epilayer. 相似文献
9.
Effects of Ⅴ/Ⅲ ratio on species diffusion anisotropy inthe MOCVD growth of non-polar a-plane GaN films 下载免费PDF全文
Non-polar a-plane (110) GaN films have been grown on r-plane (102) sapphire substrates by metal organic chemical vapour deposition. The influences of Ⅴ/Ⅲ ratio on the species diffusion anisotropy of a-plane GaN films were investigated by scanning electron microscopy, cathodoluminescence and high-resolution x-ray diffraction measurements. The anisotropy of a-plane GaN films may result from the different migration length of adatoms along two in-plane directions. Ⅴ/Ⅲ ratio has an effect on the growth rates of different facets and crystal quality. The stripe feature morphology was obviously observed in the film with a high V/III ratio because of the slow growth rate along the [100] direction. When the Ⅴ/Ⅲ ratio increased from 1000 to 6000, the in-plane crystal quality anisotropy was decreased due to the weakened predominance in migration length of gallium adatoms. 相似文献
10.
GaN-based laser diodes (LDs) with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition (MOCVD). Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser. The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells (MQWs) and super-lattices between LDs that succeed and fail to emit laser. However, the cathodoluminescence (CL) measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs. Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs. 相似文献