On the Gunn effect in two-valley semiconductors with traps

Abstract

A theory for the Gunn effect in two-valley semiconductors with traps has been developed basing on the assumption that the trapping times are field dependent and the carrier-generation rates from the traps are independent of field. The trapping process affects the threshold field for the Gunn instabilities unless the trapping rates in the two valleys are equal and independent of field. In samples which exhibit a negative differential resistance (NDR) due to field-enhanced trapping, there may not be any NDR due to intervalley carrier-transfer process even though the samples have the appropriate band structure for the occurrence of the Gunn instabilities. The possible application of this model to explain some available experimental results in discussed.