We are developing an electrostatic neutralizer operating in an atmosphere without oxygen for the organic electronics fabrication industry. As a part of the study, we investigated ion generation and neutralization characteristics of an ac-corona-discharge-type ionizer in different atmospheric gases such as ambient air, pure nitrogen, mixed N
2-O
2 and N
2-SF
6 gases, with changing the partial pressure of O
2 and SF
6, respectively. The
I-
V characteristic of the emitter shows that the negative current in nitrogen gas is significantly greater than the positive one; thus the product final voltage
VPF gives a significant deviation to a negative value (about -2 kV). However, by introducing SF
6 gas by 0.01 %,
VPF reduces to about 0 V as that in ambient air. The amount of SF
6 needed to improve the ion balance is three orders of magnitude smaller than that of O
2, due to higher electronic affinity that a SF
6 molecule has.
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