| The thesis begins with an introduction, in Chapter 1, to activities in molecular beam epitaxy (MBE) and related crystal growth methods as well as their applications in the field of optical interconnects using low-threshold lasers and high-speed photodetectors.; In Chapter 2, a Green's function of interface matching problems is presented. A very simple equation can be derived, which can provide some support to a very controversial, yet highly successful and very popular quantum dipole model for Schottky barriers and heterojunctions by J. Tersoff. A simplified model can be obtained, which eliminates the uncertainties in Tersoff's scheme and predicts very well the band offsets for several important semiconductor heterosystems including GaAs/AlAs.; Chapter 3 deals with details of MBE growth of GaAs/AlGaAs quantum well laser material on GaAs substrates. Various growth techniques and substrate orientations are discussed. The dependence of threshold current density of a GaAs/AlGaAs GRINSCH laser on quantum well thickness is experimentally studied. The experimental results are in good agreement with a qualitative analysis. A theoretical discussion of the effect of quantum well thickness on the threshold current density is used to explain the experimental results. Furthermore, this study has achieved for the first time, threshold current densities below 100 A/cm{dollar}sp2{dollar} in any semiconductor laser.; Chapter 4 presents some important issues in GaAs-on-Si research. Both the potentialities and limitations of GaAs-on-Si technology are discussed. The main advantage of GaAs-on-Si technology is the special features of Si substrates not available in GaAs substrates.; Chapter 5 discusses the experimental aspects of GaAs-on-Si laser growth by MBE. The formation and prevention of antiphase domains (APDs) are discussed. Various methods to reduce defect density are presented.; Appendix I summarizes the operation and maintenance of a Riber 2300 MBE system from a practical point of view. Only several components in this MBE system are absolutely needed to grow high quality materials. It also discusses the routine material calibrations performed. Appendix II, III, IV, V, and VI deal with the details of material processing and device fabrication. (Abstract shortened with permission of author.)... |
