9633011 Weimer This research project aims to gain fundamental understanding of the relationship between interface quality and carrier wave function overlap in quantum well semiconductor structures. The approach is to examine the influence of Al(Ga)Sb barriers on the interband coupling in model InAs/Ga(In)Sb/Al(Ga)Sb structures that comprise the active regions in type-II quantum well and quantum cascade lasers. Scanning tunneling microscopy(STM) and spectroscopy(STS) will be used to provide fundamental data on interface quality and will be related to carrier wave function overlap. The insights developed from analysis of the STM and STS data will be used in MBE growth and subsequent processing studies to optimize material quality, growth sequence, design and fabrication of type-II mid-IR lasers. %%% The research will contribute basic materials science knowledge at a fundamental level of technological relevance to several aspects of advanced electronic/photonic devices and integrated circuitry. Additionally, the knowledge and understanding gained from this research project is expected to contribute in a general way to improving the performance of advanced devices and circuits by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***
