Lateral Ordering of InAs Quantum Dots on Cross-hatch Patterned GaInP

We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs quantum dots with the aid of misfit dislocation networks. The strained layers and the InAs QDs were characterized by means of atomic force microscopy, scanning electron microscopy, and X-ray reciprocal space mapping. The QD-ordering properties of compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger ordering of QDs was observed on tensile GaInP. Furthermore, we observed a change of the major type of dislocation in GaInP layers as the growth temperature was modified.     

GaInP/AlGaInP脊形波导激光器器件结构的优化研究

通过优化脊形波导的结构参数可以降低脊形波导激光器的阈值电流,提出了实现亚微米脊宽,从而降低阈值电流的方法。针对脊形波导制作过程中蚀刻深度不易控制的问题,对GaInP/AlGaInP材料中加入蚀刻阻挡层进行了研究。     

GaAsMESFET击穿特性的研究现状与进展

栅漏击穿是限制GaAsMESFET输出功率并影响其可靠性的最主要因素之一,本文就改善GaAsMESFET击穿特性所进行的研究做了综述介绍,其中包括改变器件结构,采用新型材料和钝化等方法．     

脊形波导激光器中GaInP／AlGaInP选择蚀刻性的研究

本文制作了670nmGaInP/AlGaInP应变层量子阱脊形波导激光器,为了进一步优化工艺,在普通的单量子阱材料横向结构中嵌入30－50nm的GaIlP蚀刻阻挡层,用此种材料加工而成的控长1200μm,宽64μm的氧化条激光器的阈值电流密度为340A／cm^2,采用配比为1．0：2．5的HCl:H2O深液对GaInP/AlGaIn进行湿蚀刻研究,得到了较好的选择恂刻性结果。     

MOVPE grown Ga1−xInxAs solar cells for GaInP/GaInAs tandem applications

Lattice-mismatched Ga_1−xIn_xAs solar cells with an absorption edge between 900 and 1150 nm have been grown on GaAs substrates. Different graded Ga_1−xIn_xAs buffer layers and solar cell structures were evaluated to achieve a good electrical performance of the device. External quantum efficiencies comparable to our best GaAs solar cells were measured. The best 1 cm² cell with a bandgap energy of 1.18 eV has an efficiency of 22.6% at AM1.5g and a short circuit current density of 36.4 mA/cm². To our knowledge, this is the highest reported efficiency for a Ga_0.83In_0.17As solar cell.     

GaInP and AlInP grown by elemental source molecular beam epitaxy

We report on the use of a new, valved, solid phosphorus cracker source for the growth of phosphides by molecular beam epitaxy. The source avoids the relatively high expense and high level of toxicity associated with the use of phosphine gas and eliminates the problems commonly encountered in using conventional solid phosphorus sources. The source has been used to grow GaInP and AlInP lattice-matched to GaAs substrates. The quality of the materials reported here is comparable to the best materials grown by other techniques. Photoluminescence and Raman scattering measurements indicate that the resulting material has a high degree of disorder on the group III sublattice. The new source is shown to be a reliable and attractive alternative for the growth of these phosphide materials.     

Effect of Bragg reflector on the threshold current density in AlGaInP visible laser

The GalnP/AlGalnP layers are known as attractive materials for 600 nm band laser diodes. In this paper, a Bragg reflector between GaAs substrate and n-cladding layer was applied for the reduction in the lasing threshold. In a SCH-MQW structure, a Bragg reflector was composed of alternating λ/4n layers of AlAs and AlGaAs layers, 12.5 pairs. The effect of Bragg reflector on the threshold current and spontaneous emission intensity was appreciable because most of spontaneously emitted photons were reflected from a Bragg reflector and carriers were regenerated in the GalnP active layer.     

Positioning and doping effects on quantum dot multi‐junction solar cell performance

The positioning of InAs quantum dot (QD) layers in a triple‐junction GaInP/Ga(In)As/Ge solar cell is studied using numerical modeling techniques. An effective medium is used to describe the absorption characteristics and carrier dynamics in each QD layer. The effects of incorporating 110 layers in the emitter, base layers, as well as between these regions of the middle sub‐cell are analyzed with current–voltage characteristics and energy band diagrams. The cell with QDs positioned between the emitter and base demonstrated an efficiency of 31% under 1 sun illumination at room temperature. The performance was then increased to 31.3% by optimizing the QD region doping. Copyright © 2014 John Wiley & Sons, Ltd.     

太阳电池IV曲线中一种新光电流泄露机制研究

本论文详细分析了光伏器件中的光电流泄露机制,并在传统单二极管模型基础上,提出了一种新的分析模型以解释太阳电池研究过程中的一些异常IV曲线。新模型中主要考虑了一种位置相关的光电流泄露路径。两个具有明显电流扩展效应的GaInP太阳电池被用来研究光电流的泄露机制。这种新发展的分析模型可以很好的用来解释电池在非均匀辐照下的IV曲线,并提取了有效扩展电阻等重要电池参数。最后文中也强调了实际分析过程中的单二极管模型失效条件。论文中所使用的分析方法也适用于分析均匀光照下的IV曲线的侧向电压分布分析。     

Correlation between dark current RTS noise and defects for AIGalnP multiple-quantum-well laser diode

The correlation model between dark current RTS noise and defects for A1GalnP multiple-quantum-well laser diode is derived. Experimental results show that dark current RTS noise caused carrier number fluctuations at the interface of the heterojunction in the active region. According to this correlation model, the defect types are determined, and the defects＇ energy levels are quantitatively determined. The comer frequency of RTS noise power spectral density is analyzed. The experimental results are in good agreement with the theoretical. This result provided an effective method for estimating the deep-level traps in the active region of A1GaInP multiple quantum well laser diode.