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.