Electrical Properties and Acidity Effect of Imogolite

Abstract

Imogolites have been tested to measure their field emission (FE) properties and electrical conductivities. The field emissions from imogolite films are found to follow the Fowler-Nordheim formula, and the measured turn-on fields are at the range of 2~3 V/μm. For the exposure to oxygen gases during field emission measurements, emission currents decrease from the initial values, however, the removal of oxygen from the vacuum system, i.e., evacuation again makes the emission currents recover to or even higher than the initial ones. This strongly suggests that field emitters made from imogolites exhibit stable emissions by oxidation, i.e., under severe environmental conditions. The electrical conductivities are also measured for imogolites films as a function of water vapor pressure.