Hot Electrons in Semiconductors

Electrons in a semiconductor device pick up energy from the applied voltage or from the light that is incident on the device. They dissipate that energy by causing the semiconductor crystal lattice to vibrate more strongly. If the excess energy is given to the electrons at a faster rate than that lost to the lattice, however, the average energy and the temperature of the electrons increase very rapidly. They can become much hotter than the surrounding crystal lattice. When this happens, the electron motion in the device changes its character; current no longer increases linearly with the applied voltage; it may saturate or in some cases may even decrease with increasing voltage. Ohms law breaks down completely. How this happens, and the impact of the phenomenon on current research in semiconductors and on the electronic and optoelectronic technology is the subject matter of this book.