Development of SiGe-based Quantum Well Laser Diodes

其主要目标是利用最先进的外延技术和先进的量子电子技术，在SiGe基间接能隙量子阱中实现反转布居，从而产生受激发射。为此，人们致力于外延空穴的形成，以控制自发辐射。高反射率的Si/SiO_2布拉格反射镜和单波长中心微腔获得了较大的成功。红外增强型光电倍增管可以观察到边缘发射和表面发射之间的发光寿命差异。除了基于腔的操纵外，还利用界面工程演示了声子辅助光谱的完全抑制。三维Ge岛被用作量子点，打破了平移对称性，从而消除了原本严格的动量守恒。正如预期的那样，延长的辐射寿命支持k-对角辐射复合。至于INDIRE…更多的CT-激子复合，更多的新发现；边缘发射的大的各向异性，热化缺失的光锥限制，大的库仑屏蔽，增强的带隙重整化，由于二维限制导致的寿命缩短，掩蔽的量子限制的斯塔克效应，等等。为了比较的目的，我们重新讨论了区域折叠超晶格，试图纠正误导的概念。指出了结构无序对预测发光性质的影响。发现由于基态的大的非均匀宽度和窄的小带宽，有序的短周期超晶格不可避免地转变为无序的超晶格。从技术角度研究了器件的特性。观测到了量子井势的动态后向散射。通过监测时间分辨光谱，确认了一种有效的封闭。此外，将Si-SiO_2技术扩展到制备有序的硅点，以取代SiGe量子阱作为发光元件。较少

The chief objective is to pave the way for the realization of an inverted population in an attempt to generate stimulated emissions in SiGe-based indirect-gap quantum wells by exploiting the state-of-the-art epitaxy and advanced quantum electronics.To this end, much efforts were directed toward the epitaxial cavity formation to control the spontaneous emission. Highly-reflective Si/Sio_2 Bragg mirrors and a one-wavelength well-centered microcavity were fairly successful. A infrared-enhanced photomultiplier allowed the observation of a luminescence lifetime difference between edge- and surface-emissions.Apart from cavity-based manipulation, a total suppression of phonon-aided spectra was demonstrated using interface-engineering. Three-dimensional Ge islands were used as quantum dots to break the translational symmetry thereby removing the otherwise strict momentum conservation. Prolonged radiative lifetimes were in support of a k-diagonal radiative recombination as expected.As to indire … More ct-exciton recombinations, much was newly found ; A large anisotropy for the edge emissions, the missing light-cone limitations on thermalization, a large Coulomb screening, an enhanced band-gap renormalization, a lifetime reduction due to 2-D confinement, the masked quantum-confined Stark effects, and etc.For comparative purposes, the zone-folded superlattice was revisited in an attempt to rectify misleading concepts. Significance of structural disorders which would intimidate the predicted luminescence properties was pointed out. An ordered short-period superlattice was found to be inevitably transformed into a disordered one due to a large inhomogeneous witdth and a narrow miniband of the ground state.From technical standpoint, device characteristics were also atudied. Dynamical backscattering was observed for a quantum-well potential. A virtual blocking was confirmed by monitoring time-reolved spectra. Furthermore, the Si-SiO_2 technique was extended for the fabrication of orderly Si dots for use as light emitters replacing SiGe quantum wells. Less