ABSTRACT
As described in Chapter 2, research on the nonlinear carrier transport and current instabilities in semiconductor physics progressed significantly during the 1960s and 1970s. Especially in the 1960s, during the early years of the semiconductor physics, a huge number of papers reported on the impact-
ionization mechanism [1, 2], plasma instability [3], helical instability under longitudinal magnetic fields [4-7] and Gunn oscillation [8, 9]. The enormous efforts of the researchers can be seen in the books by Bonch-Bruevich [10] and Pozhela [3]. The 1960s were the pioneering age of semiconductor physics and modern electronics technology, following the development of
the transistor by Bardeen and Brattain in 1948 [11]. Researchers tried to find a new paradigm in solid-state electronics, which led to a breakthrough towards the brilliant age of the electronics revolution. There were investigations applying the high-nonlinearity phenomena of the carrier transport such as the Gunn effect [8] and also the tunneling effect by Esaki [12].
