Study of secondary electron emission from semiconductors induced by electrons from 20 eV to 800 eV and surface state of semiconductors

Abstract

Based on processes and characteristics of secondary electron emission (SEE), experimental data and the relations among parameters of secondary electron yield from semiconductors δ, the formula for δ in the range of 20 eV ≤ Epo ≤ 800 eV of semiconductors with Epom ≤ 800 eV as a function of Epo, Epom, atomic number Z and maximum δ (δm) was deduced and proved experimentally, where Epo and Epom are incident energy of primary electron and the Epo of δm, respectively. From the existing formula and the relation among Z, mean escape depth of secondary electrons emitted from semiconductors and primary range R at Epom deduced in this study, the formula for R in the range of 150 eV ≤ Epo ≤ 800 eV in monocrystalline semiconductors with Epom ≤ 800 eV, χ ≥ 0.6 eV and Eg ≥ 0.6 eV was successfully deduced, where χ is original electron affinity, Eg is the width of forbidden band. The method of calculating B(χreal, Eg) of semiconductor with Epom ≤ 800 eV, χreal ≥ 0.5 eV and Eg ≥ 0.6 eV and that of calculating B of semiconductor with Epom ≤ 800 eV were presented, respectively; Where B is the probability that an internal secondary electron escapes into vacuum upon reaching the surface of semiconductor, and the B(χreal, Eg) is the B relative to semiconductor with Eg and real electron affinity χreal. It can be concluded that the two methods are correct. From the analysis of calculated B, experimental Epom and relations among parameters of SEE, it can be concluded that this paper can research the surface state of semiconductor with Epom ≤ 800 eV by SEE.