Amorphous Semiconductor Switching in Melanins

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Science  01 Mar 1974:
Vol. 183, Issue 4127, pp. 853-855
DOI: 10.1126/science.183.4127.853


Melanins produced synthetically and isolated from biological systems act as an amorphous semiconductor threshold switch. Switching occurs reversibly at potential gradients two to three orders of magnitude lower than reported for inorganic thin films, and comparable to gradients existing in some biological systems. Of a number of other biological materials tested, only cytochrome c acted similarly, but at the high potential gradients reported for thin film amorphous semiconductors.