Abstract
In the near future, flash memory will face a great deal of challenges because of miniaturization and physical limit. Resistive random access memory (RRAM) has a simple structure and high endurance performance, which is one of the promising candidates for next generation memory application. Nowadays, some serious problems still need to be resolved toward the commercialization of RRAM, including stability and the mechanism. For memory devices made of polymer composites, some studies have shown that the stability can be improved by introducing nanoparticles, which also play crucial roles for switching mechanisms. As one type of biopolymers, deoxyribonucleic acid(DNA) has serious advantages, including ease of preparation, flexible and environmentally friendly. Moreover, recent studies have revealed that DNA biopolymer-nanoparticles composite may also find extensive applications in electronic and optoelectronic devices. In this study, we adopt a photochemical method to synthesize silver nanoparticles in DNA biopolymer. The characterizations of UV-VIS spectra and dynamic light scattering suggest that such photoinduced synthesis of silver nanoparticles in DNA biopolymer is more effective than that in other hosts. Then the device is fabricated based on a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes(Metal/DNA biopolymer nanocomposites/ITO). The electrical properties of the device are adjusted with increasing irradiation time, which shows write-once read many times(WORM), rewritable memory and conductor behavior. We further verify the switching mechanism by examining the electrical properties under different device areas, temperatures and electrodes. Based on the characterization results, we propose possible resistance switching mechanisms based on the formation and rupture of conductive paths. These verifications can open new avenues for various optoelectronic applications based on DNA biopolymer nanocomposites.