Electron runaway and negative differential mobility in two-dimensional electron gas in elementary semiconductors

We show that two-dimensional electron gas in silicon or germanium should ex hibit a negative differential mobility. This effect is caused by the electr on runaway since, in contrast to the three-dimensional case, such runaway t akes place even for deformation optical polar scattering. As a consequence of the electron runaway, hot electron scatter into the valleys with a large r density of states, which leads to a negative differential mobility. (C) 2 000 Published by Elsevier Science Ltd. All rights reserved.