量子阱红外探测器掺杂阱中能级的计算

量子阱中能级位置的确定是获得量子阱红外探测器其它设计参数的基础。为了提供足够的载流子跃迁,阱层一般为重掺杂层。重掺杂使半导体材料禁带宽度变窄,从而改变量子阱中能级的位置。通过对不同温度、量子阱区不同掺杂浓度条件下的量子阱材料PL 谱进行测量,得出PL 谱峰值波长对应的电子跃迁峰值能量,它与阱中基态能级的位置有关。分别计算了考虑和不考虑禁带变窄效应时的电子跃迁峰值能量,并与实验结果相比较,可以看出考虑禁带变窄效应时与实验结果相吻合,因此掺杂量子阱区能级的计算需要考虑禁带变窄效应,这样可以较为精确的得出阱中能级的位置。     

量子点量子阱中束缚态的能级结构

在有效质量近似下，考察了一个特殊量子点量子阱体系中的电子与空穴束缚态能级结构，以CdS/HgS和ZnS/CdSe构成的量子点量子阱为例进行了数值计算。结果显示，束缚态的本征能量对量子点量子阱的尺寸依赖曲线存在一些拐点，这一结果与均匀量子点体系明显不同；对某个固定的量子点量子阱结构，随量子数n的增加，CdS／HgS量子点量子阱体系中的束缚电子态的能级间隔不是单调增加的，在某些量子数n处存在峰值，而znS／CdSe量子点量子阱体系中的空穴束缚态的能级间隔则是单调增加的，这是由构成量子点量子阱的材料的有效质量比率不同造成的。     

GaAs/Al_xGa_(1-x)As量子阱红外探测器光谱特性的研究

采用MBE法制备了不同结构参数及不同阱中掺杂浓度的GaAs/AlxGa1-xAs量子阱红外探测器外延材料。通过对量子阱红外探测器材料特性和器件特性的实验测试及理论分析,研究了量子阱红外探测器的响应光谱特性,并通过薛定谔方程和泊松方程的求解,对掺杂对量子阱能级的影响做了研究。结果表明,由于应力导致的能带非抛物线性使得阱中能级发生了变化,从而引起吸收峰向高能方向发生了漂移,而阱中进行适度的掺杂没有对量子阱能级造成影响,光致发光谱实验结果与之吻合较好。在光电流谱的实验分析基础之上,分析了量子阱阱宽、Al组分与峰值探测波长λ的关系,为量子阱红外探测器的设计优化提供了参考。     

应变效应对半导体激光器输出波长的影响

假设应变效应仅出现在势阱底部,并可用方形势垒代替。在量子力学的框架下,对双阱结构的量子阱进行了讨论,并对输出波长的应变效应进行了分析。结果表明,在应变作用下,量子阱出现了能级漂移和能级分裂。正是这种效应为人们研制高性能量子阱光学器件提供了更大的设计空间。     

GaInAs/GaAs应变量子阱能带结构的计算

讨论了GaInAs/GaAs应变量子阱结构的应变效应 ,给出了量子阱层的临界厚度随In组份的变化关系。由克龙尼克 -潘纳模型计算了GaInAs/GaAs应变量子阱的量子化能级 ,给出了cl -hhl跃迁对应的发射波长随阱宽和In组份的变化关系曲线 ,并与实验测量的GaInAs/GaAs量子阱的发射波长进行了比较 ,基本一致。与此同时 ,对GaInAs/GaAs应变量子阱向长波长方向的发展也进行了计算分析 ,最后计算研究了应变量子阱中价带子能级及态密度的色散关系     

表面势垒层厚度对量子阱束缚电子态的影响

采用包络函数方法在四带k·p模型基础上计算了晶格匹配的量子阱 InP/Ca_(0.47)In_(0.53)As/InP中束缚电子能级及波函数,讨论了表面势垒层厚度对量子阱中束缚电子能级、波函数以及相应于电子基态能级与重空穴基态能级间的荧光谱峰位置的影响.文中也讨论了在势阱与势垒边界处的不同衔接条件对量子阱中束缚电子能级计算结果的影响.     

硅中δ掺杂材料的表征

利用低温生长技术抑制Ｓｂ偏析，实现了Ｓｂ的δ掺杂。同步辐射Ｘ射线反射率测量表明Ｓｂ被限制在很窄的范围，约２个内。基于量子阱可作为一个“大陷阱”的概念，测量了Ｐ型Ｂδ掺杂材料的深能级瞬态谱（ＤＬＴＳ），得到δ掺杂量子阱的子能级位置。自渝计算ＤＬＴＳ信号来自于δ掺杂量子阱的基态能级上的空以阱顶的发射。     

基于温度变化的量子阱红外探测器研究

量子阱红外探测器受到温度、压强等多种因素的影响,本文主要从温度方面进行了研究.在文献[2]的基础上,进一步推导了超晶格中热应变与温度的关系;结合量子阱红外探测器的能级公式以及波长与能级差的关系式,定量地分析了温度变化对量子阱红外探测器探测峰值波长的影响.     

MOCVD生长的硅衬底上GaAlAs/GaAs单量子阱和多量子阱激光器深能级研究

应用深能级瞬态谱(DLTS)技术研究经MOCVD生长的硅衬底上GaAlAs/GaAs 单量子阱和多量子阱激光器深能级.样品的 DLTS谱表明,在激光器的量子阱和 n-GaAlAs 限制层里均存在着一个浓度和俘获截面较大的高温电子陷阱,该陷阱可能与MOCVD生长工艺和质子轰击引进的损伤有关,它直接影响激光器的性能.DX中心和高温电子陷阱在量子阱里可能局域在GaAlAs/GaAs层的界面附近.     

量子阱间耦合对带结构的影响

用Matlab程序语言数值计算了多量子阱结构的能级,并研究了量子阱间耦合对其带结构的影响。多量子阱模型是在一个一维有限深势阱（阱边势垒高为 V0）中插入等高（Vb）等厚（b）的势垒方式建成,被分割而成的多量子阱厚度为w。通过增加插入壁垒的个数N、改变阱垒厚度比w/b 及势垒高度比V0/Vb,分别近似计算了对应的结构的能级及波函数。计算结果显示,量子阱间耦合受上述参数的强烈影响,改变参数N,w/b 或V0/Vb ,能带和带隙的宽度是可以被调节的。研究说明,量子阱的能带及带隙宽度达到期望值是完全有可能实现的。     

InGaAs/GaAs/AlGaAs应变量子阱激光器

优化设计了既能实现较小垂直方向远场发散角,又能降低腔面光功率密度的ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变层量子阱激光器,并计算了该结构激光器实现基横模工作的脊形波导结构参数。利用分子束外延生长了ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器材料并研制出基横模输出功率大于１４０ｍＷ,激射波长为９８０ｎｍ的脊形波导应变量子阱激光器,其微分量子效率为０．８Ｗ／Ａ,垂直和平行结平面方向远场发散角分别为２８°和６．８°     

GaInNAs/GaAs量子阱结构基态光跃迁的能量

从理论和实验两个方面对GaInNAs/GaAs量子阱结构基态的光跃迁能量进行研究.在理论计算过程中,分别采用电子有效质量近似法和双能级推斥模型计算了GaInNAs合金的电子空穴分立能级的能量及其带隙能,讨论了由应变引起的带隙变化量.将理论计算结果与光致发光的实验结果进行比较,两者符合得很好.并简单分析了N的加入对GaInNAs合金带隙能产生的影响.     

On the delta-type doping of GaAs-based heterostructures with manganese compounds

Heterostructures, which incorporate GaAs/InGaAs/GaAs quantum wells and are doped with spatially remote monatomic Mn layers, are formed on GaAs(001) substrate under conditions of multilayer buildup by the method of molecular-beam epitaxy. Combined studies of the obtained samples were performed by the method of secondary-ion mass spectrometry, by measurements of X-ray diffraction, and using a transmission electron microscope. The heterostructures under study with a doping impurity concentration amounting to 0.5 single layers are elastically stressed and demonstrate planar clearly defined interfaces without visible extended or point defects. A method for visualization of the distribution of the manganese concentration in the three-dimensional GaAs matrix in the vicinity of a quantum well is suggested. According to experimental results, there is a probability for manganese diffusion into the GaAs/InGaAs/GaAs quantum well when the critical thickness of the GaAs buffer layer is decreased to a value smaller than 3 nm.     

AlInGaAs/AlGaAs应变量子阱增益特性研究

采用Shu Lien Chuang方法计算了AlInGaAs/AlGaAs应变引起价带中重、轻空穴能量变化曲线,在Harrison模型的基础上详细地计算了AlInGaAs/AlGaAs和GaAs/AlGaAs量子阱电子、空穴子能级分布并且进一步研究了这两种材料在不同注入条件下的线性光增益.进一步计算比较可以得出AlInGaAs/AlGaAs应变量子阱光增益特性要优于GaAs/AlGaAs非应变量子阱增益特性,因此AlInGaAs/AlGaAs应变量子阱半导体材料应用于半导体激光器比传统GaAs/AlGaAs材料更具优势.     

Specific Features of the Electrochemical Capacitance–Voltage Profiling of GaAs LED and pHEMT Structures with Quantum-Confined Regions

GaAs light-emitting (LED) and HEMT structures with δ-doped regions, InGaAs/GaAs quantum wells, and surface layers of InAs/GaAs quantum dots were studied by means of the electrochemical capacitance- voltage profiling technique. The concentration depth profiles of free charge carriers were obtained. Charges accumulated in quantum wells and quantum dots, as well as the doping levels of the emitter and δ layers were determined. The band structure and free carrier density distribution over the depth of the samples with different quantum well geometry were simulated. The specific features of electrochemical capacitance- voltage profiling in different heterostructure types are analyzed. A method of integration of capacitance- voltage curves at each etching stage was suggested. This method provides the efficient separation of responses from closely located layers, particularly the quantum well and δ layer.     

Mixing of hole states in GaAs/AlAs(110) heterostructures

States in the AlAs/GaAs(12)/AlAs(110) quantum well and AlAs(6)/GaAs(12)(110) superlattice are considered. For analysis of mixing of light- and heavy-hole states in these structures, a parameter-dependent set of basis functions is suggested and the values of the parameter at which one of the functions describes basically heavy-hole states and the other light-hole states are determined. For the energy region considered in the study, four energy levels are determined in the AlAs/GaAs(12)/AlAs(110) quantum well and, correspondingly, four minibands in the AlAs(6)/GaAs(12)(110) superlattice. Analysis shows that the first and fourth levels in the quantum well and the first and fourth minibands in the superlattice are related basically to heavy-hole states. The other two states in the quantum well and the second and third minibands in the super-lattice are structurally more complex: in these states and minibands, the hole states are noticeably mixed. In these minibands, states are substantially separated in space and in spin.     

Comparative Analysis of the Optical and Physical Properties of InAs and In0.8Ga0.2As Quantum Dots and Solar Cells Based on them

Semiconductors - InAs and In0.8Ga0.2As quantum dots in a GaAs matrix as well as GaAs solar cells with quantum dots of both types in the i-region are obtained by metalorganic vapor-phase epitaxy. As...     

Multiple Quantum Well SEED Arrays for Flip-Chip Bonding Optoelectronic Smart Pixels

The investigation on GaAs/AlGaAs multiple quantum well Self Electro-optic Effect Device (SEED) arrays for flip-chip bonding optoelectronic smart pixels has been reported. In order to increase the absorption of the intrinsic region, the number of quantum well periods is defined as 90 pairs. The GaAs/AlGaAs multiple quantum well devices are designed for 850nm operation. The measurement results under applied biases show the good optoelectronic characteristics of elements in SEED arrays.     

快速热退火对高应变InGaAs/Ga As量子阱的影响

用固态分子束外延技术生长了高应变In0.45Ga0.55As/GaAs量子阱材料. 研究了快速热退火对高应变InGaAs/GaAs量子阱材料光学性质的影响. 本文采用假设InGaAs/GaAs量子阱中的In-Ga原子扩散为误差函数扩散并解任意形状量子阱的薛定谔方程的方法，对不同退火温度下InGaAs/GaAs量子阱室温光致发光峰值波长拟合，得到了In原子在高应变InGaAs/GaAs量子阱中的扩散系数以及扩散激活能（0.88eV) .