共查询到20条相似文献,搜索用时 31 毫秒
1.
Dependence of the differential gain and the external differential quantum efficiency on the composition of InGaAsP barrier layers were investigated for 1.3 μm InGaAsP-InGaAsP compressively strained layer (SL) multiquantum well (MQW) lasers. In this investigation, we compared between SL-MQW lasers and unstrained MQW lasers having the same well thicknesses and the same emitting wavelength in order to clarify the effect of strain for each barrier composition. As a result It has been found that the barrier composition has large influence on the differential gain and the external differential quantum efficiency in the SL-MQW lasers. Narrower band-gap barrier means little effect of strain on the differential gain due to the electron overflow from a well layer, while wider band-gap barrier means degradation in the differential gain and the external differential quantum efficiency due to the nonuniform injection of hole into a well layer. In this experiment, the barrier composition of 1.05 μm is suitable for 1.3 μm InGaAsP-InGaAsP SL-MQW lasers to realize large differential gain and high external differential quantum efficiency simultaneously 相似文献
2.
Higashi T. Ikeda T. Ogita S. Morito K. Soda H. 《Quantum Electronics, IEEE Journal of》1995,31(2):286-292
We investigated polarization dependence of photo-detection in strained layer multiple quantum-well (SL-MQW) lasers for time compressive multiplex (TCM) application. The polarization dependence of SL-MQW lasers is larger than that of bulk lasers because of the quantum effect. To improve the polarization dependence of photo-detection, we theoretically and experimentally analyzed the effect of strain quantity on the polarization dependence, and found that large tensile strained quantum-well structure is suitable for the small polarization independence of 0.8 dB and low threshold current characteristics. Moreover, we achieved smaller polarization dependence less than 0.5 dB by applying reverse bias voltage in the photo-detection mode 相似文献
3.
InGaAs/AlGaAs量子阱中量子尺寸效应对PL谱的影响 总被引:1,自引:1,他引:0
本文采用金属有机物化学气相淀积(MOCVD)方法设计并生长了两组InGaAs/A1GaAs应变多量子阱,量子阱的厚度分别为3nm和6nm,对其光致发光谱(PL)进行了研究,二者的发光波长分别为843nm和942nm,用有限深单量子阱理论近似计算了由于量子尺寸效应和应变效应引起的InGaAs/A1GaAs量子阱带隙的改变,这解释了两组样品室温下PL发射波长变化的原因。 相似文献
4.
The differential gain and the linewidth enhancement factor of 1.5- mu m multiple-quantum-well (MQW) active layers were measured with and without biaxially compressive strain as functions of the wavelength and the carrier density. These parameters of the strained MQW layer reveal stronger carrier-density dependence than those of the unstrained MQW layer. Most significantly, an anomalous increase in the linewidth enhancement factor is observed at high carrier densities. These characteristics are explained by a simple theoretical analysis.<> 相似文献
5.
Chong-Yi Lee Meng-Chyi Wu Hung-Pin Shiao Tian-Tsorng Shi Wen-Jeng Ho 《Solid-state electronics》1999,43(12):2141-2146
In this article, we describe the growth and characterization for 1.3 μm InAsP/InP strained multiple quantum well (SMQW) laser diodes (LDs) with separate confinement heterostructure grown at 580°C by metalorganic chemical vapor deposition. The grown strained single quantum well (SSQW) stack and strained multiple quantum well (SMQW) structures are characterized using double-crystal X-ray diffraction and photoluminescence (PL) to confirm the structural and optical qualities for practical device applications. The InAsP/InP SSQW stack grown at 580°C appears to be extremely abrupt, uniform, free of misfit dislocations and narrow PL half width. Although the InAsP/InP SMQWs grown at 580°C maintain its structural integrity throughout the deposition sequence, the slightly broader PL half width for InAsP/InP SMQW structure is attributed to the dislocations resulted from a large net strain. Laser emission can be achieved by using the InAsP/InP SMQWs and the lasing wavelength is in a good agreement with our designed structure. The experimental data of broad-area and ridge waveguide LDs are described in detail. 相似文献
6.
Yu. N. Drozdov Z. F. Krasil’nik D. N. Lobanov A. V. Novikov M. V. Shaleev A. N. Yablonskiĭ 《Semiconductors》2006,40(3):338-341
The effect of the predeposition of strained Si1 ? x Gex layers (x ≤ 20%) on photoluminescence (PL) of self-assembled Ge(Si)/Si(001) islands is studied. A shift of the PL peak related to dome-shaped islands (domes) to lower energies, with respect to the PL peak related to pyramidal islands is observed; this shift is related to a much larger height of the domes compared to that of pyramids. It is found that, as the Ge content in the Si1 ? x Gex layer (x) becomes higher than 0.1, two separate peaks appear in the broad PL band related to the islands; these peaks are attributed to the zero-phonon and phonon-assisted optical transitions in the islands. The appearance of these transitions is caused by a change of the TO-phonon type involved in radiative recombination: a TOGe-Ge phonon is replaced by a TOSi-Ge phonon with a shorter wavelength. 相似文献
7.
H. Yasaka K. Takahata N. Yamamoto M. Naganuma 《Photonics Technology Letters, IEEE》1991,3(10):879-882
The gain saturation coefficients were measured for strained and unstrained multiple quantum-well distributed feedback (MQW-DFB) lasers. The gain saturation coefficient depends on the deviation of the laser's transverse-magnetic (TM) mode gain peak wavelength from its transverse-electric (TE) mode gain peak wavelength delta lambda , which is related to the strain on the active-layer wells. The gain saturation coefficient epsilon increased with increasing compressed strain on the active-layer wells. The coefficient epsilon of the unstrained MQW DFB laser with a wavelength deviation delta lambda of -350 AA was 2.45*10/sup -17/ cm/sup 3/, and epsilon increased up to 12.6*10/sup -17/ cm/sup 3/ in the SL-MQW DFB laser with a wavelength difference delta lambda of -890 AA.<> 相似文献
8.
2μm InGaSb/AlGaAsSb strained quantum wells and a tellurium-doped GaSb buffer layer were grown by molecular beam epitaxy(MBE).The growth parameters of strained quantum wells were optimized by AFM, XRD and PL at 77 K.The optimal growth temperature of quantum wells is 440℃.The PL peak wavelength of quantum wells at 300 K is 1.98μm,and the FWHM is 115 nm.Tellurium-doped GaSb buffer layers were optimized by Hall measurement.The optimal doping concentration is 1.127×1018 cm-3 and the resistivity is 5.295×10-3Ω·cm. 相似文献
9.
M. Hopkinson J. P. R. David E. A. Khoo A. S. Pabla J. Woodhead G. J. Rees 《Microelectronics Journal》1995,26(8):805-810
We report growth and characterization details of lattice matched and coherently strained InxGa1−xAs/InP quantum well structures grown on misoriented [111]B InP substrates. Photoluminescence from a range of such structures, grown on substrates with optimum misorientation, show linewidths as good or better than equivalent [100] layers. Multiquantum well (MQW) samples with relatively modest compressive strain show X-ray diffraction data characteristic of highly uniform pseudomorphic quantum wells. With increased strain (x = 0.63), relaxation is evident through a degradation of the diffracted peak widths and through the observation of defects in the surface morphology. Fabricated strained p-i(MQW)-n diode structures exhibit low reverse leakage current densities (e.g. j = 6 μA/cm2). Room temperature photocurrent measurements on these devices show a strong excitonic blue shift (15 nm) with applied bias, as a consequence of the built-in piezoelectric field. The rate of peak shift, up to 8 nm/V, demonstrates excellent potential for low voltage optical modulator applications at around 1.55 μm wavelength. 相似文献
10.
绝缘体上张应变锗材料是通过能带工程提高锗材料光电性能得到的一种新型半导体材料,在微电子和光电子领域具有重要的应用前景.采用微电子技术中的图形加工方法以及利用锗浓缩的技术原理,在绝缘体上硅(SOI)材料上制备了绝缘体上张应变锗材料.喇曼与室温光致发光(PL)测试结果表明,不同圆形半径的绝缘体上锗材料张应变均为0.54%.对于绝缘体上张应变锗材料,应变使其发光红移的效果强于量子阱使其发生蓝移的效果,总体将使绝缘体上张应变锗材料的直接带发光峰位红移.同时0.54%张应变锗材料的直接带发光强度随着圆形半径的增大而减弱,这主要是因为圆形半径大的样品其晶体质量较差.该材料可进一步用于制备锗微电子和光电子器件. 相似文献
11.
采用室温Raman散射和低温光致发光(PL)谱,对以TMG,固体As和固体In作为分子束源的MOMBE法生长的GaAs/In_xGa_(1-x)As(x=0.3)单层异质结构和多量子阱结构中InGaAs应变层的临界厚度进行了实验研究。由应变引起的Raman散射峰位移,以及PL谱峰位置与应变和无应变状态下一维有限深势阱跃迁能量计算结果的比较可见,在In组分含量x=0.3的情况下,临界厚度H_c≤5nm,小于能量平衡理论的结果,而与力学平衡模型的理论值相近。 相似文献
12.
利用GaAs基上InGaAs应变层制备有序排列的InAs量子点 总被引:1,自引:1,他引:0
在GaAs基InxGa1-xAs(x=0.15)应变层上生长了InAs量子点(QD)层,通过分析各层之间的应力状况和位错的演变过程,配合生长过程中对反射式高能电子衍射仪(RHEED)实时监测,并观察生长后的表面形貌,发现可以通过控制应变层厚度来控制应变层表面布纹结构的宽度,而且在应变层厚度低于位错增殖的临界厚度时布纹宽度较窄.如果同时控制QD层在刚刚出点,则QD主要沿着较窄的布纹结构排列,从而得到有序排列的QD 相似文献
13.
双偏振双波长混合应变量子阱激光器 总被引:1,自引:0,他引:1
本文报道了以混合应变量子阱结构为有源区的激光器。对有源区分别采用体材料、匹配量子阱、压应变量子阱和混合应变量子阱结构的激光器进行了比较。混合应变量子阱激光器能同时工作于两种偏振模式,而且两种偏振模式的激射波长不同。结合实验结果,我们可以看出在混合应变量子阱结构中,从偏偏自发辐射谱峰值长差不能推断两种量子陆的能带填充效应大小。 相似文献
14.
多孔硅PL谱的影响因素分析 总被引:3,自引:0,他引:3
通过阳极氧化电化学方法制备了多孔硅,并在室温下对不同条件下制得的多孔硅光致发光谱(PL谱)进行系统的分析.结果表明,随着阳极电流密度、阳极化溶液浓度和时间的增大,多孔硅的PL谱峰将发生"蓝移",并且PL峰强也显著增加,但过大的电流密度、阳极化溶液浓度和时间将导致PL峰强下降.另外,还发现PL谱存在多峰结构,而多孔硅在空气中放置时间的延长将引起其PL的短波峰"蓝移"和强度下降,但对长波峰只引起强度减弱,并不影响其峰位.PL谱的多峰结构可以认为是由于样品中同时存在"树枝"状和"海绵"状两种微观结构所产生的,在这个假设下,用多孔硅氧化后发光中心从硅表面移到二氧化硅层及量子限制模型能够解释上述现象. 相似文献
15.
16.
O. J. Pitts S. P. Watkins C. X. Wang J. A. H. Stotz M. L. W. Thewalt 《Journal of Electronic Materials》2001,30(11):1412-1416
We present a study of the growth of strained ultrathin GaSb quantum well (QW) layers in a GaAs host crystal by organometallic
vapor phase epitaxy (OMVPE). We report surface anisotropy features observed by reflectance difference spectroscopy (RDS) during
exposure of the GaAs (001) surface to trimethylantimony (TMSb) and during subsequent growth interruption. We demonstrate the
formation of a floating layer of Sb during growth of GaAs over GaSb quantum well layers. The periodic nature of the RDS signal
during growth of multiple quantum well (MQW) structures allows us to construct time-resolved RDS spectra, detailing the evolution
of the surface anisotropy. We show how x-ray diffraction (XRD) data may be used to determine the graded compositional profile
resulting from Sb segregation at the GaAs/GaSb interface. Photoluminescence (PL) spectra at 2 K from MQW structures exhibit
two peaks below the GaAs bandgap. The lower-energy peak, which we attribute to a type-II transition at the GaSb/GaAs interface,
shifts logarithmically with excitation power density. The higher energy peak shows no shift with excitation power, and is
attributed to a transition occurring within the graded barrier layers. 相似文献
17.
Kenji Uchida Masahiko Kawata Tao Yang Shigeo Goto Tomoyoshi Mishima Atsuko Niwa Jun Gotoh 《Journal of Electronic Materials》1999,28(3):246-251
We have examined how a growth interruption, caused by closing group-III sources, affects the crystalline quality of InGaN/GaN
quantum-well (QW) structures grown by metalorganic vapor phase epitaxy. The QW samples were characterized by their photoluminescence
(PL), and by atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy dispersive x-ray (EDX) microanalysis.
The PL peak wavelength was strongly dependent on the duration of the growth interruption and on the number of QW layers. AFM
measurements revealed that the size of the open hexagonally shaped pits in the QW structures increased dramatically as the
interruption duration was lengthened. Through TEM and EDX microanalysis, we found that the formation of these hexahedronal
pits, formed due to the growth interruption, causes a large fluctuation in the In composition, especially around the pits,
and the presence of such pits in an underlying QW layer strongly affects the In incorporation into the upper QW layers, leading
to significant growth-rate variation in an InGaN QW layer and red-shifting of the PL spectra when a multiple-QW structure
is grown. 相似文献
18.
采用气态源分子束外延系统生长了InAsP/InP应变多量子阱,研究了H 注入对量子阱光致发光谱的影响以及高温快速退火对离子注入后的量子阱发光谱的影响.发现采用较低H 注入能量(剂量)时,量子阱发光强度得到增强;随着H 注入能量(剂量)的增大,量子阱发光强度随之减小.H 注入过程中,部分隧穿H 会湮灭掉量子阱结构界面缺陷,同时H 也会对量子阱结构带来损伤,两者的竞争影响量子阱发光强度的变化.高温快速退火处理后,离子注入后的量子阱样品发光峰位在低温10K相对于未注入样品发生蓝移,蓝移量随着H 注入能量或剂量的增大而增加.退火过程中缺陷扩散以及缺陷扩散导致的阱层和垒层之间不同元素互混是量子阱发光峰位蓝移的原因. 相似文献
19.
用MOCVD方法生长了3种InGaAs/Al0.2Ga0.8As应变多量子阱(MQWs)样品,用于研究在气相中TMIn的含量对MQWs的发光波长和半峰宽(FWHM)以及在X射线中零级峰位的影响。研究表明,随着In组分在MQW中的增加,MQWs中应变也随之增加,这是造成FWHM增大的原因。同时也研究了应变MQWs中In组分与气相中TMIn含量的关系,为准确设计和控制MQWs的组分提供了依据。 相似文献
20.
M. V. Shaleev A. V. Novikov A. N. Yablonskiĭ O. A. Kuznetsov Yu. N. Drozdov D. N. Lobanov Z. F. Krasil’nik 《Semiconductors》2007,41(11):1356-1360
The effect of growth temperature on photoluminescence is studied for structures with Ge(Si) islands grown on relaxed SiGe/Si(001) buffer layers and confined between strained Si layers. It is shown that, with decreasing growth temperature in the range from 700 to 630°C, the photoluminescence peak associated with the islands shifts to lower energies, which is due to the increase in Ge content in the islands and to suppression of degradation of the strained Si layers. The experimentally observed shift of the photoluminescence peak to higher energies with decreasing temperature from 630 to 600°C is attributed to the change in the type of the islands from domelike to hutlike in this temperature range. This change is accompanied by an abrupt decrease in the average height of the islands. The larger width of the photoluminescence peak produced by the hut islands in comparison with the width of the peak produced by the domelike islands is interpreted as a result of a wider size dispersion of the hutlike islands. 相似文献