Semiconductor Physics and Photonics

本文提出的研究工作包括三个部分：非线性材料的分子束外延生长，这些材料的半导体物理，以及使用这些材料的非线性器件。人们的注意力最初将集中在不断增长的基于GaAs的结构和器件上，如Bulk、Single。以及多量子阱样品，法布里·珀罗单片反射镜标准具，以及用于非线性波导和量子点结构的起始材料。我们将研究样品的光学性质，特别是激子以下光谱区域的线性和非线性光学性质。研究高激发下的吸收尾部及其饱和不仅是非常有趣的物理问题，而且有助于表征生长样品的质量，对于优化器件的设计和运行是必不可少的。吸收尾、载流子寿命和带隙非线性的偏振相关性将作为量子阱宽度、生长条件和器件设计的函数进行研究。微光刻技术和各向异性刻蚀技术将被用于制造非线性波导结构，如定向耦合器和Mach.Zehnder干涉仪，以及半导体标准具阵列。将研究控制载流子寿命的方法，从而研究非线性器件的响应时间，并将器件设计为在相对较低的速度下低功率操作和用于超快光开关。

The research effort proposed here consists of three parts: MBE growth of nonlinear materials, semiconductor physics of those materials, and nonlinear devices using those materials. Attention will be focused initially on growing GaAs.based structures and devices such as bulk, single. and multiple.quantum.well samples, Fabry.Perot etalons with monolithic mirrors, as well as starting material for nonlinear waveguides and quantum dot structures. The optical properties of the samples will be studied, with special emphasis on the linear and nonlinear optical properties in the spectral regions below the exciton. Studying the absorption tail and its saturation under high excitation is not only very interesting physics, but also helpful for characterizing the quality of the grown samples, and essential for optimum device design and operation. Absorption tail, carrier lifetime, and polarization dependence of the bandgap nonlinearities will be investigated as functions of quantum well widths, growth conditions, and device design. Microlithography and anisotropic etching techniques will be used, to fabricate nonlinear waveguide structures such as directional couplers and Mach.Zehnder interferometers, as well as arrays of semiconductor etalons. Methods to manipulate the carrier lifetime and, hence, the response time of the nonlinear devices will be investigated, and devices will be designed for both low.power operation at relatively low speed and forultrafast optical switching.