Threshold switching in melanin

Abstract

Threshold-switching measurements of synthetic melanin confirm that this organic semiconductor switches to a low-resistance state in low electric fields as reported by McGinness et al. Time-dependent current-vs-voltage curves show that the time to traverse the negative-differential-resistance (NDR) segment is much slower than would be expected from electronic-switching mechanisms. Double-pulse measurements add to the evidence that thermal effects dominate electronic effects in melanin. A pseudomemory effect was found in melanin.