Research on Residual Gas Adsorption on Surface of Hexagonal Boron Nitride-Based Memristor

As a promising nonvolatile memory device with two ends, the memristor has received extensive attention for its industrial manufacture. Density functional theory was used to analyze the adsorption properties of residual gas on hexagonal boron nitride (h-BN)-based memristor model surfaces with Stone-Wales-5577 grain boundary defects [h-BN(SW)]. First, by calculating the adsorption energy, geometric parameters, and charge transfer, we identified the most stable adsorption sites for hydrogen atoms (H-TB1) and H₂ molecules (H₂-TN2). We observed a tendency toward chemisorption for hydrogen atoms and physical adsorption for H₂ molecules at these sites. Furthermore, two coadsorption configurations were formed by introducing H₂ molecules and hydrogen atoms into single adsorption configurations: namely H-TB1_H₂-TN1TN2 and H₂-TN2_H-TB1TN1TN3. In the case of hydrogen-based configuration, there is weak dissociation of the H₂ molecule, which does not facilitate hydrogen atom adsorption. However, adjacent hydrogen atoms tend to form stable dimers, while excess hydrogen atoms have a tendency to weakly chemisorb in the case of H₂-based configuration. The pristine h-BN surface is more favorable for hydrogen atom migration compared to the h-BN(SW) surface due to its higher adsorption energy. On the h-BN(SW) surface, hydrogen atoms tend to migrate inward from the center of adjacent heptagonal boron nitride rings while coadsorption has a minimal impact on their vertical migration as well as that of H₂ molecules. This work provides theoretical insights into the H/H₂ trace gas interaction during h-BN wafer-level fabrication for memristor devices.