Phototunable memories and reconfigurable logic applications based on natural melanin

Abstract

The saturation of Moore's law and the finality of Dennard scaling highlight the need for new data-storage approaches employing different physical mechanisms. Due to the low operation voltage, multibit storage and cost-effective manufacturability, memristive devices are considered to be one of the most attractive alternatives to conventional silicon-based memory. Typically, memristive devices can be switched to a low resistance state or a high resistance state by electrical SET/RESET operations, respectively. Recent years have witnessed a surge of research interest in optoelectronic memories, where tunable switching characteristics, coexistence of volatile and non-volatile behaviours, multilevel programming capability and programming/erasing steps can be achieved optically. In this work we introduce an electro-photoactive memristive device based on natural melanin with favorable electrical and optical properties. The device shows reproducible bipolar resistive switching with a low SET voltage (0.2 V) and an ON/OFF ratio over 10⁴. The SET voltage can be easily tuned from 0.2 V to 1.2 V by varying the wavelength or the intensity of the optical input. Due to this phototunable switching characteristic, light-driven switchable NAND and NOR operations have been realized on a melanin-based circuit.