Energy Distribution of Electrons Emitted from Silicon Surface-Barrier Diodes

Abstract

The energy distribution of electrons emitted from surface-barrier diodes made of p-type silicon with aluminum contacts has been investigated in an attempt to clarify the behavior of electrons in a high electric field in silicon. Free electrons have been produced in the p-type silicon by irradiated light and accelerated in the depletion layer of a reverse-biased diode to escape into vacuum from the cesium-treated surface of the thin aluminum contact. Energy distributions of the emitted electrons have been measured under various conditions using the retarding field method. The energy distributions of the electrons in the silicon have been obtained from those of the emitted electrons. They cover the energy region from 1.5 to 4 eV above the conduction-band bottom of silicon. Different energy distributions have been found for [111] and [100] directions of the accelerating electric field. By using Keldysh's theory with known parameters, the mean-free paths of hot electrons between phonon scattering have been determined to be 45 and 52 Å by fitting the experimental energy distributions to the calculated ones for acceleration of electrons in the [111] direction and for acceleration of electrons in valleys of easy acceleration in the [100] direction respectively.