Adjusted NIEL calculations for estimating proton-induced degradation of GaInP/GaAs/Ge space solar cells

The non-ionizing energy loss (NIEL) values for protons in solar cells should be modified by taking into account the distribution of the Bragg damage peak in the active region to calculate the corresponding displacement damage dose. In this paper, based upon a thin target approximation, a new approach is presented to modify NIEL values for protons on a GaAs sub-cell. Adjusted NIEL values can be used to estimate the degradation induced by protons on GaInP/GaAs/Ge triple-junction space solar cells.     

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。     

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．     

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。     

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.     

HBT电压控制振荡器的相位噪声

研究了电压控制振荡器（ＶＣＯ）的相位噪声与构成该振荡器的有源器件的低频噪声的关系,测试了ＳｉＢＪＴ、ＡｌＧａＡｓ／ＧａＡｓ ＨＢＴ和ＧａＩｎＰ／ＧａＡｓ ＨＢＴ的低频噪声,并分析了各自低频噪声产生的原因,提出了选择ＧａＩｎＰ／ＧａＡｓ ＨＢＴ ＶＣＯ来实现微波固体振荡器低相位噪声化这一发展方向。     

Growth of order/disorder heterostructures in GaInP using a variation in V/III ratio

CuPt ordering, resulting in formation of a natural monolayer {111} superlattice, occurs spontaneously during organometallic vapor phase epitaxial growth of Ga_0.52In_0.48P. The degree of order is found to be a function of the input partial pressure of the phosphorus precursor (P_P) during growth. This is thought to be mainly due to the effect of P_P on the surface reconstruction. A change in order parameter is associated with a change in the bandgap energy. Thus, a practical application of ordering is the production of a heterostructure by simply changing the flow rate of the P precursor during growth. Examination of transmission electron microscopy data and photoluminescence spectra indicates that order/disorder (O/D) (really less ordered on more ordered) and D/O heterostructures formed by growth using PH₃ at a temperature of 620°C are graded over several thousands of Å: The ordered structure from the lower layer persists into the upper layer. Similar results were obtained at 620°C when the first layer was grown using PH₃ (V/III=160) and the second using tertiarybutylphosphine (TBP) (V/III=5). The use of a temperature of 670°C to produce heterostructures using either PH₃ or TBP yields a totally different behavior. Abrupt D/O and O/D heterostructures can be produced by changing P_P during the growth cycle. The cause of this difference in behavior is not entirely clear. However, it appears to be related to a very slow change in the surface reconstruction, measured using surface photo absorption, when the PH₃ partial pressure is changed at 620°C.     

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.     

Fill factor as a probe of current‐matching for GaInP2/GaAs tandem cells in a concentrator system during outdoor operation

Designing a tandem solar cell for use in a concentrator system is challenging because: (a) the conditions are variable, so solar cells rarely operate under optimal conditions, and (b) the conditions are not controlled, so any design problems are difficult to characterize. Here, we show how the fill factor can be used as a diagnostic tool to either verify correct system design and operation or to help identify a problem. We give particular attention to the detection of spectral skewing by the concentrator optics, as this can reduce the performance of GaInP₂/GaAs tandem cells and is difficult to characterize. The conclusions are equally valid for GaInP₂/GaAs/Ge triple‐junction cells. Copyright © 2007 John Wiley & Sons, Ltd.     

0.28-2.80 MeV质子辐射对空间实用GaInP/GaAs/Ge多结太阳电池性能的影响

用0.28、0.62和2.80 MeV质子束模拟空间辐射对国产MOCVD方法制备的GaInP/GaAs/Ge多结电池进行质子辐射效应研究.辐照注量为1×1012 cm-2.对电池的辐射效应用I-V特性和光谱响应测试进行分析.结果表明:随质子辐照能量的增加,太阳电池性能参数Isc,Voc,Pmax和光谱响应的衰降幅度均减小,0.28MeV质子辐照引起电池性能衰降最显著;低能质子辐照引起中间GaAs电池光谱响应衰降更明显.