Screening and impurity ionization energy in semiconductors

TL;DR

This paper investigates how the electrostatic field around charged impurity ions in semiconductors affects their ionization energy, revealing that high carrier concentrations can lead to zero effective ionization energy.

Contribution

It introduces the consideration of electrostatic field energy around impurity ions in semiconductors, showing its impact on ionization energy reduction.

Findings

Electrostatic field energy decreases ionization energy.

At high carrier concentrations, ionization energy approaches zero.

Electrostatic effects are significant in impurity ionization analysis.

Abstract

Usually microscopic electrostatic field around charged impurity ions is neglected when the ionization energy is concerned. The ionization energy is considered to be equal to that of a lonely impurity atom. Here the energy of the electrostatic field around charged impurity ions in semiconductor is taken into account. It is shown that the energy of this field contributes to decrease in the effective ionization energy. At high enough current carriers concentration the effective ionization energy becomes zero.