Field emission into nonpolar organic liquids

Abstract

Field emission into nonpolar liquids was studied for n-hexane, 2,2,4-trimethylpentane, and tetramethylsilane at 275–334 K. The current–voltage dependence was found to vary depending on the liquids and the temperature, and was reproduced qualitatively on the basis of the Fowler–Nordheim theory modified by taking account of the space charge effect. The quasifree electron energy (the electron energy in a liquid with reference to that in vacuum) was estimated from the current–voltage dependence in a space charge-free region, i.e., from the apparent work functions of the metal emitter (tungsten tip) in the liquids, to be 0, −0.6, and −1.3 eV for n-hexane (as a standard), trimethylpentane, and tetramethylsilane, at 293 K. These values lie in the same order as determined previously by the photoelectric emission from a metal surface in the liquids, though the dependence on the liquids is more pronounced in the present field emission study.