1.55μmSi1—xGex光波导在Si1—xGex／Si多量子阱探测器集成的优…

对１。５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽，高和腐蚀深度分别为８，３和２．６μｍ，２）对ＳＩ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ，２３个周期的６ｎｍＳｉ０．５ＧＥ０．５＋１８ｎｍＳｉ组成，长度约２ｍｍ。     

1.55μmSi_(1-x)Ge_x光波导与Si_(1-x)Ge_x/Si多量子阱探测器集成的优化设计

对１．５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱（ＭＱＷ）红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽、高和腐蚀深度分别为８、３和２．６μｍ；２）对Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ、２３个周期的６ｎｍＳｉ０．５Ｇｅ０．５＋１７ｎｍＳｉ组成，长度约２ｍｍ。结果表明，这种结构器件的内量子效率可达８８％。     

波导与探测器吸收层垂直耦合结构中的光学耦合分析

利用几何学理论分析了波导与探测器吸收层之间的光学传播情况，以硅基波导与ＧｅＳｉ／Ｓｉ多量子阱ＰＩＮ探测器吸收层主分析对象，说明光学耦合效率与两层介质的折射率分布及吸收层长度的关系。     

多量子阱平面光波导的有限元分析

本文利用有限元法分析了多量子阱平面光波导的传播特性,给出了任意阱数多量子阱光波导.TE模和TM模的有效折射率和TE模的强度分布.结果表明:r(势阱与势垒的厚度比)值的改变,影响波导中导模的模式数目、有效折射率、双折射和强度分布;并发现在某些情况下,均方根近似是不适用的.     

多量子阱平面光波导的有限元分析

本文利用有限元法分析了多量子阱平面光波导的传播特性,给出了任意阱数多量子阱光波导_TE模和TM模的有效折射率和TE模的强度分布.结果表明:γ(势阱与势垒的厚度比)值的改变,影响波导中导模的模式数目、有效折射率、双折射和强度分布;并发现在某些情况下,均方根近似是不适用的.     

ZnSe－ZnTe多量子阱室温下的反射型皮秒激子光双稳

本文首次研究了ＺｎＳｅ－ＺｎＴｅ多量子阱在室温下的反射型皮秒激子光双稳，实验结果表明，ＺｎＳｅ－ＺｎＴｅ多量子阱在室温下的反射型皮秒光双稳的阈值光强和对比度分别为１．１ＭＷ／ｃｍ２和６：１．根据测量得到的ＺｎＳｅ－ＺｎＴｅ多量子阱在室温下的激子吸收光谱及激子的非线性吸收理论，归结ＺｎＳｅ－ＺｎＴｅ多量子阱室温下的皮秒光双稳的主要非线性机理为ＺｎＳｅ－ＺｎＴｅ多量子阱的激子饱和吸收引起的折射率变化．     

用有效折射率法和有限元法分析多量子阱条形光波导

本文提出了一种快速和精确分析多量子阱(MQW)条形光波导的新算法。它基于有效折射率法和有限元法的结合。首先,由等效的平面波导替换多量子阱条形结构,用有效折射率法从原来问题得到平面波导的折射率分布;然后,用有限元法计算等效结构中E_(mn)~x模和E_(mn)~y模的传播常数和场强分布。文中给出了任意阱数和不同宽度多量子阱的对称结构和不对称结构的结果。     

SCH量子阱激光器的光学限制特性

通过对描述半导体激光器基本光波导方程的数值求解，分析了ＡｌＧａＡｓ／ＧａＡｓ分别限制量子阱激光器的光学限制特性，比较了不同缓变结构及多量子阱结构的光学限制因子。     

Si_（1－x）Ge_x／Si脊形波导X型分支器的研制

采用分子束外延方法制作低损耗Ｓｉ１－ｘＧｅ／Ｓｉ异质结脊形光波导,在Ｘ型交叉波导上实现了Ｓｉ１－ｘＧｅｘ／Ｓｉ光分支器的功能．设计中采用了ＳｉＧｅ大截面脊形波导的单模条件和交叉波导传输特性分析的结果．Ｘ型光分支器的实现为进一步研制Ｓｉ１－ｘＧｅｘ／Ｓｉ光开关和光电调制器积累了经验．     

Si1—xGex／Si脊形波导X型分支器的研制

采用分子束外延方法制作低损耗Ｓｉ１－ｘＧｅ／Ｓｉ异质结脊形光波导，在Ｘ型交叉波导上实现了Ｓｉ１－ｘＧｅｘ／Ｓｉ光分支器的功能，设计中采用了ＳｉＧｅ大截面脊形波导的单模条件和交波导传输特性分析的结果。Ｘ型光分支器的实现为进下Ｓｉ１－ｘＧｅｘ／Ｓｉ光开关和光电调制器积累了经验。     

锗硅量子阱中近带边光跃迁的理论和实验研究

本文研究了SiGe/Si量子阱中近带边光跃迁的产生机制,对由杂质无规分布引起的近带边光跃迁给出了一个物理模型。用此模型计算了光跃迁偶极矩,给出了跃迁偶极矩的上限。提出了未掺杂SiGe/Si量子阱中近带边光跃迁的一种跃迁机制,认为是Ge原子周围波函数畸变的集体行为。用MBE方法生长了掺杂SiGe/Si量子阱材料,在低温下观测到近带边光跃迁。     

ELECTRO-LUMINESCENCE AND PHOTO-LUMINESCENCE FROM STRAINED SiGe/Si QUANTUM WELL

Photo-luminescence and electro-luminescence from step-graded index SiGe/Si quantum well grown by molecular beam epitaxy is reported. The SiGe/Si step-graded index quantum well structure is beneficial to the enhancing of electro-luminescence. The optical and electrical properties of this structure are discussed.     

SiGe/Si量子阱的低温光荧光和电注入发光

使用Si-MBE生长了阶梯形折射率分布SiGe/Si量子阱材料,在低温下观测到无声子参与的光荧光和电注入发光。阶梯形折射率分布SiGe/Si电子阱结构有利于提高发光效率。讨论了这种结构的光学和电学特性。     

Characterization of the linear optical properties of a multiple quantum well structure in the sheet-model approximation

The possibility of determining the linear optical response tensor of a multiple quantum well (MQW) structure from optical reflection spectra is discussed. Taking into account local-field effects, the optical parameters of the MQW system are derived directly from the sheet conductivity tensor of the individual quantum well. For an amorphous Si/SiO₂ MQW structure deposited on a crystalline Si substrate, both s- and p-polarized reflection spectra were measured at different angles of incidence in the near-infrared and visible frequency regions. It was shown that the s-polarized spectra can be characterized by means of only one (complex) parameter, whereas in general it is impossible to account for the p-polarized spectra parametrically in a full range of angles of incidence even with four angular independent parameters. Finally, it was demonstrated that Feibelman's d-parameters can only be used to describe the experimental spectra at near-normal and grazing angles of incidence.     

InGaAsP/InP evanescent mode waveguide optical isolators and their application to InGaAsP/InP/Si hybrid evanescent optical isolators

We theoretically investigated InGaAsP/InP evanescent mode waveguide optical isolators and proposed their application to InGaAsP/InP/Si hybrid evanescent optical isolators. InGaAsP/InP evanescent optical isolators are composed of semiconductor optical amplifier (SOA) waveguides having InGaAsP multiple quantum well (MQW) active layer and upper InGaAsP waveguide layer with ferromagnetic layer. Optical isolation is obtained for evanescent optical mode in the InGaAsP waveguide layer. InGaAsP/InP/Si hybrid evanescent optical isolators are theoretically proposed based on the idea of InGaAsP/InP evanescent optical isolators. InGaAsP/InP/Si hybrid evanescent optical isolators are composed of ferromagnetic metal loaded silicon evanescent waveguides with wafer-bonded InGaAsP/InP optical gain material. The optical isolation and propagation loss are discussed with the structure of silicon evanescent waveguides, and optical isolation of 8.0 dB/mm was estimated. The concept of semiconductor evanescent mode optical isolators is feasible with InP based photonic integrated circuits and advanced silicon photonics.     

硅表面硅镱键合与量子级联结构的发光

用纳秒强激光脉冲制备了纳米硅和硅表面的硅镱键合结构,检测了纳米硅表面硅镱键合的发光特性,并对这种结构相应的光致发光(PL)和电致发光(EL)的动力学机理进行了研究。观察到纳米硅表面硅镱键合在700nm附近尖锐的强发光峰,结合第一性原理计算认为是硅镱键合在弯曲纳米硅表面的局域态发光;利用纳秒脉冲激光沉积技术(PLD)制备多晶硅薄膜,发现由硅镱界面的失配形成表面的突触,其上的硅镱键合产生带隙中的电子局域态,该局域态发光分布在1250~1650nm波长范围,有增强的EL发光;用PLD方法制备硅镱多层膜量子级联结构,测量到光通信窗口的多个发光峰,并观察到随膜层数增加且发光峰增多。     

Si杂质扩散诱导InGaAs/AlGaAs量子阱混杂的研究（英文）

光学灾变损伤(COD)常发生于量子阱半导体激光器的前腔面处,极大地影响了激光器的出光功率及寿命。通过杂质诱导量子阱混杂技术使腔面区波长蓝移来制备非吸收窗口是抑制腔面COD的有效手段,也是一种高效率、低成本方法。本文选择了Si杂质作为量子阱混杂的诱导源,使用金属有机化学气相沉积设备生长了InGaAs/AlGaAs量子阱半导体激光器外延结构、Si杂质扩散层及Si 3 N 4保护层。热退火处理后,Si杂质扩散诱导量子阱区和垒区材料互扩散,量子阱禁带变宽,输出波长发生蓝移。退火会影响外延片的表面形貌,而表面形貌则可能会影响后续封装工艺中电极的制备。结合光学显微镜及光致发光谱的测试结果,得到825℃/2 h退火条件下约93 nm的最大波长蓝移量,也证明退火对表面形貌的改变,不会影响波长蓝移效果及后续电极工艺。     

Dependence of Optical Absorption in Silicon Nanostructures on Size of Silicon Nanoparticles

The amorphous silicon nanoparticles (Si NPs) embedded in silicon nitride (SiN_x) films prepared by helicon wave plasma-enhanced chemical vapor deposition (HWP-CVD) technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride (nc-Si/SiNx) thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particlesize-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.     

Photoluminescence and X-ray characterisation of Si/Si1−xGex multiple quantum wells

We present an experimental approach to correlate optical and structural properties of Si/Si_1−xGe_x multiple quantum wells as determined by photoluminescence (PL) and X-ray diffraction, respectively. The optical properties of the quantum wells were characterised by studying the dependence of luminescence on temperature and excitation density. An enhanced PL yield and an increased quenching temperature were observed for a sample grown at 650°C as compared to one grown at 600°C. Pronounced interdiffusion across the multiple quantum well interfaces as well as significant lattice distortions within the SiGe layers have been observed.