MAXIMUM SECONDARY ELECTRON YIELDS FROM SEMICONDUCTORS AND INSULATORS

Based on the processes and characteristics of secondary electron emission and the formula for the yield due to primary electrons hitting on semiconductors and insulators, the universal formula for maximum yield δpm due to primary electrons hitting on semiconductors and insulators was deduced, where δpm is the maximum ratio of the number of secondary electrons produced by primary electrons to the number of primary electrons. On the basis of the formulae for primary range in different energy ranges of Wp0m, characteristics of secondary electron emission and the deduced universal formula for δpm, the formulae for δpm in different energy ranges of Wp0m were deduced, where Wp0m is the primary incident energy at which secondary electron yields from semiconductors and insulators, δ, are maximized to maximum secondary electron yields from semiconductors and insulators, δm; and δm is the maximum ratio of the number of total secondary electrons produced by primary electrons and backscattered electrons to the number of primary electrons. According to the deduced formulae for δpm, the relationship among δm, δpm and high-energy back-scattering coefficient r, the formulae for parameters of δ and the experimental data as well as the formulae for δm in different energy ranges of Wp0m as a function of χ, Eg, r and Wp0m were deduced, where χ and Eg are the original electron affinity and the width of forbidden band, respectively. The scattering of δm was analyzed, and calculated δm values were compared with the values measured experimentally. It was concluded that the deduced formulae for δm were found to be universal for δm.