InP is a key semiconductor for the production of optoelectronic and photonic devices. Its related compounds, such as InGaAsP alloy, have been realized as very important materials for communication in the 1.3 and 1.55 micron spectral regions. Furthermore, the applications on InP and related compounds have extended to other areas that include laser diodes, light emitting diodes, photodetectors, waveguides, photocathodes, solar cells, and many other applications. The topics presented in this book have been chosen to achieve a balance between the properties of bulk materials, doping, characterization, applications, and devices. This unique volume, featuring chapters written by experts in the field, provides a good starting point for those who are new to the subject and contains detailed results and in depth discussions for those who are experts in the field.