Tech Briefs

Reliable memory devices can be realized within a single macromolecule based on natural DNA.

Motivated by the demand for an even larger storage capacity in the information era, research efforts have been devoted to the development of more efficient and cost-effective memory elements.

Many digital data storage infrastructures are constructed based on the building block with a resistive switching (RS) behavior, where resistances can be reversibly changed by applying different voltages. So far, the RS effect has been demonstrated in many metal oxide and organic materials, such as SiO2, HfO2, P3HT, PVK, etc. The use of biomaterials in electronic devices has also drawn considerable attention recently, driven by the rapid development of technology coupled with the growing interests toward green electronics.

Biomaterials are abundant, eco-friendly, and suitable for large-area implementation, which make them of great interest for applications such as flexible displays and wearable technologies. As green electronics continue to advance, the development of a facile approach to fabricate a biomaterial-based memory device becomes critical to pave the way for implementation of low-cost and green electronic devices.

Previous studies have been done on the use of biomaterials for resistive memory devices. Some involve DNA sequence control, while others may require external doping of guest components. The addition of nanoparticles, for example, provides an easy route to tune the electrical properties of the composites. However, uniform dispersion and compatibility of the hybrid composites may be difficult to control. Furthermore, some reported devices need to be operated under controlled environmental conditions. These features increase complexity when it comes to practical implementation and device integration.

This study reports on the fabrication of resistive switching devices based on natural DNA biomaterial. The raw DNA material is isolated from salmon milt, which is randomly sequenced with a wide range of distribution of base pairs. Such DNA can be readily extracted from biological species and is abundant in nature.

In the present device, the structure consists of a spin-coated DNA layer sandwiched by two electrodes without DNA sequence control or external doping of nanoparticles. The fabricated devices show a reliable resistive switching behavior with low switching voltages, data retention longer than 104 s, and more than 180 times in memory endurance under ambient conditions. The device also shows multi-level memory characteristics, in which the current levels can be controlled by reset voltages.

To study the underlying switching mechanisms, the electrical properties are examined under different fabrication parameters and measurement conditions. This demonstration shows that reliable memory devices operated under ambient conditions can be realized within a single macro-molecule based on natural DNA biomaterial. The ease of material handling and device fabrication may lead to future development for biomaterial-based multifunctional devices or green electronic devices.

This work was done by Huei-Yau Jeng, Tzu-Chien Yang, Li Yang, Hsin-Lung Chen, and Yu-Chueh Hung of National Tsing Hua University and James G. Grote for the Air Force Research Laboratory. AFRL-0259