Bulk negative-resistance effects in semiconductors

Summary form only given, as follows. In semiconductors which have a current - voltage characteristic containing a differential negative resistance region, oscillations are developed at an appropriate bias voltage. The oscillations are due to high field domains traversing the sample. In this paper we discuss briefly some mechanisms which can give rise to negative-resistance effects, and treat in detail the transferred electron effect. Particular reference is made to recent calculations on GaAs, InP and CdTe. A description is given of the field distribution within a domain and of domain motion along a sample. The transferred electron oscillator is analysed as a source of microwave power, and an indication given of the optimum properties required from the semiconductor. Experimental results, mainly relating to the generation of X-band and K-band radiation from epitaxial samples, are included.