Carrier waves in semiconductors I: Zero temperature theory

A detailed treatment of the space-charge waves or carrier waves which are associated with drifting carriers in a semiconductor is given. These waves have a phase velocity comparable to that of the drifting carriers, but normally have very high loss. This dielectric relaxation loss may be radically decreased by utilizing the interaction between two sets of carriers, working with semiconductors of small cross section, or semiconductors placed against high permittivity materials. Gain may be obtained by using special materials such as GaAs, or by the use of interactions between two sets of carriers in the presence of a magnetic field. The treatment given neglects the effect of diffusion so as to keep the mathematics simple and emphasize the physics of the problem. In a later paper, methods of taking diffusion into account will be given.