Dx Centers: Donors in Aigaas and Related Compounds (Defect and Diffusion Forum , Vol 108)

During the last 25 years, the behaviour of donors in III-V alloys has been the subject of a very extensive research effort. The research emphasis on A1GaAs compounds is motivated by the industrial importance of A1GaAs/GaAs heterojunction-based devices. As seeing it now, "the DX center problem" - the behaviour of donors in III-V alloys - has been shown to be unexpectedly difficult to understand. To determine the microscopic nature of the DX nature is still a challenging problem. After being part of the ESPRIT-BASIC consortium on DX centers, the authors have undertaken the effort of presenting their very recent results and views. Eight comprehensive chapters, with a detailed effort to cross-analyze the information obtained from the various experimental techniques, contain a critical discussion of those results in the light of the theoretical models available. A significant amount of new results, not previously published, are also presented. The main questions regarding the DX centers are categorized into three sections: "Microscopic structure models" of the DX centers atomic and electronic structure, the amount and nature of lattice distortion upon electron capture, the charge state of the DX center ground state; "Fundamental properties", such as thermal activation energy, capture barrier for electrons and holes, effects in magetotransport, electron emission and capture kinetics and optical properties; "Minimization of DX effects in III-V devices" - optimum doping procedure, selection of donor species, alloy compositions and device structures that avoid/minimize DX deleterious effects. These topics are presented in six chapters. Special chapters dedicated to other III-V alloys and critical discussions of the experimental results versus leading theoretical models, have also been included. The book is addressed to the community interested in the physics and engineering of semiconductors, including senior undergraduate and graduate students involved in III-V semiconductor materials and device research. This book follows the volume edited by J.C. Bourgoin, "The Physics of DX Centers in GaAs", which represents the discussions on the topic up to 1989.