共查询到20条相似文献,搜索用时 593 毫秒
1.
为了获得高拉曼增益特种石英光纤,提高拉曼光纤 放大器增益,本文研究了铌酸锂掺杂石英光纤的拉曼散射增强特性,采用改进化学气相沉积(MCVD)法制备出了铌酸锂掺杂石英光纤样品,其在1550nm 波长处的传输损耗为5dB/km。测得了铌酸锂掺杂石英光纤的拉曼光谱,并与相同长度的常 规单模光纤拉曼 光谱进行了对比,发现铌酸锂掺杂石英光纤具有更高的拉曼散射强度,在几个主要峰位处, 铌酸锂掺杂石 英光纤的拉曼散射强度为常规单模光纤的3.8~4.8倍。同时,搭建了 拉曼光纤放大器系统,分别测得铌酸 锂掺杂石英光纤和常规单模光纤的拉曼散射放大增益。实验结果表明,铌酸锂掺杂石英光纤 拉曼放大增益 约是常规单模光纤的2倍。因此,铌酸锂掺杂石英光纤作为拉曼光纤放大器的增益介质将可 取代常规单模 光纤,并能有效地提高拉曼光纤放大器的放大效果。 相似文献
2.
3.
报道了MBE生长的CdTe/Cd1-xMnxTe:In调制掺杂应变层多量子阱材料的光荧光光谱,低温下观察到一个由多电子-单个空穴散射引起的很强的费密边奇异的发光现象,对应于费密边能量位置发光峰有一个很强的增加,使整个发光锋具有明显的非对称性。分析讨论了引起费密边奇异现象的物理机制,测量了77K和GdTe/Cd1-xMnxTe:In样品的调制光谱,与荧光光谱进行比较,结果进一步支持了本文的结论。还测 相似文献
4.
5.
用电化学C-V和I-V特性分析的方法,对Mg掺杂在MOCVD生长AlGaInP发光二极管(LED)的影响进行了研究。通过电化学C-V分析,确定了在生长结构中Mg掺杂从有源层到GaP窗口层由高到低的情况;用I-V特性分析的方法对器件结构进行了分析,发现了异常的实验结果。同时理论计算得到了同型结(N^ -N,P^ -P)的势垒高度和空间电荷区的宽度,由此得到了在同型结两侧浓度比不同时的差异,极好的解释了异常的I-V测试结果。 相似文献
6.
杂质Si对InAs自组织量子点均匀性的影响 总被引:1,自引:1,他引:0
研究了较低掺杂浓度时InAs量子点中直接掺杂Si对其发光特性的影响.光致发光谱(PL)的测量表明,与未掺杂样品相比,掺杂样品发光峰稍微蓝移,同时伴随着发光峰谱线明显变窄.该结果表明,在生长InAs层时直接掺杂,有利于形成大小分布更均匀的小量子点.该研究对InAs自组织量子点在器件应用方面有一定的意义. 相似文献
7.
8.
针对四元系AlGaInP红光发光二极管在制备过程中,材料的掺杂特性对于器件性能影响巨大,尤其是AlInP限制层材料的掺杂,对于器件光电性能具有明显的影响。在实际生产过程中P型掺杂浓度的波动非常大,明显影响到红光LED的发光均匀性。从不同的AlInP限制层P型掺杂浓度与LED发光亮度的关系入手,探索研究AlInP限制层P型掺杂浓度对LED发光亮度影响的规律,所得研究结果对于LED的器件结构设计以及MOCVD外延材料生长有一定的指导意义。 相似文献
9.
10.
报道了MBE生长的CdTe/Cd1-xMnxTe:In调制掺杂应变层多量子附材料的光荧光光谱,低温下观察到一个由多电子-单个空穴散射引起的很强的费密边奇异的发光现象,对应于费密边能量位置发光峰有一个很强的增加,使整个发光锋具有明显的非对称性.分析讨论了引起费密边奇异现象的物理机制,测量了77K下CdTe/Cd1-xMnxTe:In样品的调制光谱,与荧光光谱进行了比较,结果进一步支持了本文的结论.还测量了费密迪奇异随温度的变化,结果表明此现象在Ⅱ—Ⅵ族半导体多量子附材料中比Ⅲ─V族材料强得多. 相似文献
11.
12.
13.
M. S. Oh N. H. Kim C. H. Lee H. S. Park J. Y. Kim G. Pak T. I. Kim 《Journal of Electronic Materials》1995,24(11):1683-1686
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. 相似文献
14.
XIA Wei LI Shu-qiang WANG Ling MA De-ying ZHANG Xin WANG Fu-xun JI Gang LIU Ding-wen REN Zhong-xiang XU Xian-gang MEI Liang-mo 《光电子快报》2006,2(4):263-265
650 nm AIGalnP/GalnP laser diodes with compressively strained MQW active layer have been successfully fabricated by means of single epitaxy growth. The threshold current is 6.4 mA,at 40 mA CW operation, the fundamental transverse-mode still remains, and the output power and the slope efficiency can reach 34 mW and 1.1 mW/mA respectively. The dead output power in CW operation can reach 66 mW at a saturation current of 88 mA. During 200 h burn in test,the laser diodes show good stabilization with a degradation of less than 8 %. 相似文献
15.
Dumitrescu M. Toikkanen L. Laakso A. Tukiainen A. Rimpilainen V. Pessa M. 《Photonics Technology Letters, IEEE》2007,19(22):1819-1821
Compositional and strain limitations are often restricting the emission wavelength from quantum-well (QW) lasers. The letter presents simulation and experimental results on the effects of including thin higher bandgap layers into GalnP QWs emitting in the short red wavelength range. These were considered "spiked" single QWs since the thin higher bandgap layers used in our studies varied in composition and led to carrier wavefunctions that are like perturbed single QW wavefunctions rather than wavefunctions of coupled QWs. The edge-emitting lasers having up to four-monolayer AlGalnP "spikes" in the QWs had an emission blueshift of up to 25 nm, whereas the degradation of other laser characteristics was in line with the degradation observed when similar emission blueshift was generated by conventional QW modification. 相似文献
16.
对蓝宝石衬底上的InGaN/GaN和InGaN/AlGaN多量子阱结构和经激光剥离去除衬底的InGaN/GaN和InGaN/AlGaN多量子阱结构薄膜样品,进行了光致发光谱、高分辨XRD和喇曼光谱测量.PL测量结果表明,相对于带有蓝宝石衬底的样品,InGaN/GaN多量子阱薄膜样品的PL谱峰值波长发生较小的蓝移,而InGaN/AlGaN多量子阱薄膜样品的PL谱峰值波长发生明显的红移;喇曼光谱的结果表明,激光剥离前后E2模的峰值从569.1减少到567.5cm-1.这说明激光剥离去除衬底使得外延层整体的压应力得到部分释放,但InGaN/GaN与InGaN/AlGaN多量子阱结构中阱层InGaN的应力发生了不同的变化.XRD的结果证实了这一结论. 相似文献
17.
提出了一种基于硼酸溶液的GaAs/InP低温晶片键合技术,实现了GaAs/InP基材料间简单、无毒性的高质量、低温(290℃)晶片键合。GaAs/InP键合晶片解理截面的扫描电子显微镜(SEM)图显示,键合界面整齐,没有裂缝和气泡。通过键合过程,InP上的In0.53Ga0.47As/InP多量子阱结构转移到了GaAs基底上。X射线衍射及荧光谱显示,键合后的多量子阱晶体质量未变。二次离子质谱(SIMS)和Raman光谱图显示,GaAs/InP键合晶片的中间层厚度约为17 nm,界面处B元素有较高的浓度,键合晶片的中间层很薄,因此可以得到较好的电学、光学特性。 相似文献
18.
<正> 鉴于准二维激子在半导体多量子阱的光学过程中所起的决定性的作用,可以预期,在共振喇曼散射中,激子应是主要的中间态。但由于多量子阱电子结构、激子、声子的研究只是在近几年才有比较深入的理解,迄今尚无系统的喇曼散射的微观理论。本文将给出二维各向同性近似和电偶极近似下的多量子阱喇曼散射微观理论。 相似文献
19.
H. C. Kuo J. M. Kuo Y. C. Wang C. H. Lin H. Chen G. E. Stillman 《Journal of Electronic Materials》1997,26(8):944-948
We report the determination of band offset ratios, using photoluminescence excitation measurements, for GaInP/GaAs and AlInP/GaAs
quantum wells grown by gas-source molecular beam epitaxy. To reduce the uncertainty related to the intermixing layer at heterointerfaces,
the residual group-V source evacuation time was optimized for abrupt GalnP/GaAs (AlInP/GaAs) interfaces. Based upon thickness
and composition values determined by double-crystal x-ray diffraction simulation and cross-sectional transmission electron
microscopy, the transition energies of GalnP/GaAs and AlInP/GaAs quantum wells were calculated using a three-band Kane model
with varying band-offset ratios. The best fit of measured data to calculated transition energies suggests that the valence-band
offset ratio (γ band discontinuity) was 0.63 ± 0.05 for GalnP/GaAs and 0.54 ± 0.05 for AlInP/GaAs heterostructures. This result
showed good agreement with photoluminescence data, indicating that the value is independent of temperature. 相似文献
20.
Selenium doping of GalnP was performed using atomic layer epitaxy. The dependence of the n-type carrier concentration of Se-doped
GalnP on growth temperature was quite different from that of Se-doped GaAs. Reducing growth temperature was found to be a
crucial factor in achieving high n-type doping levels in as-grown Se-doped GalnP. 相似文献