Negative resistance arising from transit time in semiconductor diodes

The structural simplicity of two-terminal compared to three-terminal devices indicates the potential importance of two terminal devices employing semiconductors and having negative resistance at frequencies properly related to the transit time of carriers through them. Such negative resistances may be combined with unsymmetrically transmitting components, such as gyrators or Hall effect plates, to form dissected amplifiers that may be made to simulate conventional three-terminal amplifiers and operate at high frequencies. The characteristics of several structures are analyzed on the basis of theory and it is found that negative resistances are possible for properly designed structures.