排序方式: 共有13条查询结果,搜索用时 15 毫秒
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采用k·p方法理论,考虑了极化电场和自由载流子重新分布等因素,通过薛定谔方程和泊松方程自洽求解得到InGaN/AlInGaN,InGaN/GaN,InGaN/InGaN,InGaN/AlGaN量子阱导带和价带的能带结构,并由此计算了不同量子阱结构的自发发射谱.分析对比发现AlInGaN材料特有的自发极化和压电极化效应在阱垒界面处形成的极化电荷对量子阱发光特性有重要的影响.以AlInGaN为垒,优化其中各元素的组分可以减小极化电场的影响,提高量子阱自发发射谱强度.同时,综合考虑了极化电荷和势垒高度的影响,提出了具体的优化方法,并给予了物理解释. 相似文献
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采用k·p方法理论,考虑了极化电场和自由载流子重新分布等因素,通过薛定谔方程和泊松方程自洽求解得到InGaN/AlInGaN,InGaN/GaN,InGaN/InGaN,InGaN/AlGaN量子阱导带和价带的能带结构,并由此计算了不同量子阱结构的自发发射谱.分析对比发现AlInGaN材料特有的自发极化和压电极化效应在阱垒界面处形成的极化电荷对量子阱发光特性有重要的影响.以AlInGaN为垒,优化其中各元素的组分可以减小极化电场的影响,提高量子阱自发发射谱强度.同时,综合考虑了极化电荷和势垒高度的影响,提出了具体的优化方法,并给予了物理解释. 相似文献
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Surface structural, electronic and electrical properties of the quaternary alloy AlInGaN/GaN heterostructures are investigated. Surface termination, atomic arrangement, electronic and electrical properties of the (0001) surface and (10–11) V-defect facets have been experimentally analyzed using various surface sensitive techniques including spectroscopy and microscopy. Moreover, the effect of sub-band gap (of the barrier layer) illumination on contact potential difference (VCPD) and the role of oxygen chemisorption have been studied. 相似文献
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M.A. Abid H. Abu Hassan Z. Hassan S.S. Ng S.K. Mohd Bakhori N.H.Abd. Raof 《Materials Science in Semiconductor Processing》2011,14(2):164-169
High-resolution X-ray diffraction (HR-XRD) with rocking curve, atomic force microscopy (AFM) and photoluminescence (PL) spectroscopy have been performed on high-quality quaternary AlxInyGa1−x−yN thin films at room temperature. The AlxInyGa1−x−yN films were grown on c-plane (0 0 0 1) sapphire substrates with AlN as buffer layers using a molecular beam epitaxy (MBE) technique with aluminum (Al) mole fractions x ranging from 0.0 to 0.2 and constant indium (In) mole fraction y=0.1. HR-XRD measurements confirmed the high crystalline quality of these alloys without any phase separation. The X-ray rocking curve of AlxInyGa1−x−yN films typically shows full widths at half maximum (FWHM) intensity between 14.4 and 28.8 arcmin. AFM measurements revealed a two-dimensional (2D) growth mode with a smooth surface morphology of quaternary epilayers. PL spectra exhibited both an enhancement of the integrated intensity and an increasing blueshift with increased Al content with reference to the ternary sample In0.1Ga0.90N. Both effects arise from Al-enhanced exciton localization. PL was used to determine the behavior of the energy band gap of the quaternary films, which was found to increase with increasing Al composition from 0.05 to 0.2. This trend is expected since the incorporation of Al increases the energy band gap of ternary In0.1Ga0.90N (3.004 eV). We have also investigated the bowing parameter for the variation of energy band gaps and found it to be very sensitive on the Al composition. A value of b=10.4 has been obtained for our quaternary AlxInyGa1−x−yN alloys. 相似文献
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Yi-Keng Fu Yu-Hsuan Lu Ren-Hao Jiang Bo-Chun ChenYen-Hsiang Fang Rong Xuan Yan-Kuin SuChia-Feng Lin Jebb-Fang Chen 《Solid-state electronics》2011,62(1):142-145
Near ultraviolet light-emitting diodes (LEDs) with quaternary AlInGaN quantum barriers (QBs) are grown by atmospheric pressure metalorganic vapor phase epitaxy. The indium mole fraction of AlInGaN QB could be enhanced as we increased the TMG flow rate. Both the wavelength shift in EL spectra and forward voltage at 20 mA current injection were reduced by using AlInGaN QB. Under 100 mA current injection, the LED output power with Al0.089In0.035Ga0.876N QB can be enhanced by 15.9%, compared to LED with GaN QB. It should be attributed to a reduction of lattice mismatch induced polarization mismatch in the active layer. 相似文献
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We have demonstrated the growth of quaternary AIlnGaN compounds at different growth temperatures and pressures with metalorganic chemical vapor deposition (MOCVD). The optical properties of the samples have been investigated by photoluminescence (PL) at different temperatures. The results show that the sample grown at higher temperature (850℃) exhibits the best optical quality for its sharp band edge luminescence and weak yellow luminescence. The AIlnGaN exhibited three-dimensional (3D) growth mode at higher pressure. The band edge emission almost disappeared. With the optimization of AIInGaN growth parameters, we replaced the traditional barrier in InGaN/GaN multiple quantum wells (MQWs) with AllnGaN barriers. The peak wavelength for the InGaN/AIInGaN-MQW based light emitting diodes (LEDs) was very stable at various injection current levels because of the polarization-matched InGaN/AIInGaN MQWs. 相似文献
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近年来短波长紫外LED巨大的应用价值引起了人们的高度关注,成为了全球半导体领域研究和投资的新热点。本文综合分析了AlGaN材料的生长、碎裂、掺杂和欧姆接触等问题,对UV—LED的发展历程、技术路线和研究进展进行了详细介绍,并展望了未来发展方向。 相似文献
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A 2DEG charge density based drain current model for various Al and In molefraction mobility dependent nano-scale AlInGaN/AlN/GaN HEMT devices 总被引:1,自引:1,他引:0
We present a two-dimensional electron gas(2DEG) charge-control mobility variation based drain current model for sheet carrier density in the channel.The model was developed for the AlInGaN/AlN/GaN highelectron -mobility transistor.The sheet carrier density model used here accounts for the independence between the Fermi levels Ef and ns along with mobility for various Al and In molefractions.This physics based ns model fully depends upon the variation of Ef,u0,the first subband E0,the second subband E\,and ns.We present a physics based analytical drain current model using ns with the minimum set of parameters.The analytical results obtained are compared with the experimental results for four samples with various molefraction and barrier thickness.A good agreement between the results is obtained,thus validating the model. 相似文献
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The operating parameters such as the internal quantum efficiency (ηi),internal loss (αi) and transparent threshold current density (J0) of double quantum well laser diodes were investigated and identified using the program,Integrated System Engineering-Technical Computer Aided Design (ISE-TCAD). Various thicknesses (6,7,8,10,12 nm) of AlxInyGa1-x-yN barriers with (3 nm) Al0.08In0.08Ga0.84N wells as an active region were studied. The lowest threshold current (Ith),and the highest output power (Pop) were 116 ... 相似文献