Impact Ionization of Centers in Solids by Electrons Accelerated by an Electric Field

✍ Scribed by F. Cardon

• Book ID: 105385503
• Publisher: John Wiley and Sons
• Year: 1963
• Tongue: English
• Weight: 641 KB
• Volume: 3
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.19630030217

✦ Synopsis

Abstract

The probability of impact ionization of centers by electrons which have been accelerated in an electric field is calculated using time dependent perturbation theory. The wave function for a bound electron is taken to be of the form Ψ = (λ^3^/π)^1/2^ exp (‐ λ__r__) and the effective mass approximation is used for the band. A modified Boltzmann function is used for the electrons in the band, and it is shown that impact ionization can only be important, in high resistivity materials, if the electric field is high even to raise the electron temperature well above lattice temperature. The effect on the current‐voltage characteristic is examinated for two simple cases and it is found that a steep rise due to impact ionization can occur. Electrons trapped in neutral centres are somewhat more important than electrons in negative centres, whilst electrons in positive centres are very much less important. It is also shown that the effect of impact ionization will, in general, only be important if most of the electrons which are released are trapped in other shallow traps.