Chuanhua Duan

Developing a Nanofluidic Volatile Memory Cell

PROJECT DESCRIPTION
Nanofluidics is the study and application of fluid flow in and around nanometer-sized objects. Since its emerging in early 2000s, this new research field has gained great attention because of numerous anomalous transport phenomena at the nanoscale and corresponding exciting applications in bio-medicine and energy. One of the ongoing research efforts in the nanofluidic field is to create and study nanofluidic components analogous to the basic electrical components, aiming for developing ionic based logic and computation devices. Although nanofluidic diode and transistor have been invented and widely studied, nanofluidic volatile memory cell, which can store binary information in the form of “0” and “1”, has never been demonstrated before.

Recently we discovered a very interesting electrokinetic nanoparticle trapping phenomena near nanopore where a nanoparticle-blocked nanopore can show two distinctive states upon different electrical stimuli. Specifically, when negatively charged nanoparticles with a size larger than the diameter of nanopore are electrokinetically driven toward the nanopore under a negative bias, a nanoparticle will be electrokinetically trapped near the nanopore, which partially blocks the nanopore without making any physical contact with the nanopore. The trapped nanoparticle can be immediately released once the negative bias is removed or a positive bias is applied. Consequently, the nanopore will be in the closed state under a negative bias and in the open state under a positive bias. The closed state also has volatile memory characteristics which is very similar to electronic volatile memory cell.

The goal of this project is to develop a nanofluidic volatile memory cell based on the electrokinetic trapping phenomenon. As our current nanopore system only has two electrical connections and the reading voltage is also the writing voltage for both the open (0) and closed (1) states, it is impossible to use one voltage to read these two states for the current nanopore system. However, this function is required for real volatile memory cell. To solve this problem, we propose to add another electrical (writing) connection to the system, to control nanoparticles moving toward or away from the nanopore and thus separate the reading and writing process. We will integrate a microchannel with two electrical connections beneath the nanopore. The connection right below the nanopore will be connected to the reading line, where a negative bias is always applied. Large positive/negative voltage can be applied to the other connection in the microchannel to write the state 0/1. Students/teachers working in this project will help fabricate the integrated nanopore-microchannel device and investigate the performance of this new nanofluidic volatile memory cell.

LABORATORY MENTOR
Yixin Xu, Rami Yazbeck 

RESEARCH GOALS
– Develop a nanofluidic volatile memory cell based on the electrokinetic nanoparticle trapping and nanopore-microchannel integration
– Optimize the reading and writing voltages for the nanofluidic memory cell
– Investigate the performance of the memory cell

LEARNING GOALS
– Gain basic understanding of electrokinetic trapping near nanopore
– Learn how to conduct electrokinetic nanoparticle trapping experiment
– Learn how to use inverted microscope
– Learn how to evaluate the performance of a memory cell

Learn more about Associate Professor Duan on his faculty page.