Graphene-Based Physically Unclonable Functions with Dual Source of Randomness

Abstract

There is growing interest in systems with randomized responses for generating physically unclonable functions (PUFs) in anticounterfeiting and authentication applications. Atomic-level control over its thickness and unique Raman spectrum make graphene an attractive material for PUF applications. Herein, we report graphene PUFs that emerge from two independent stochastic processes. Randomized variations in the shape and number of graphene adlayers were achieved by exploiting and improving the mechanistic understanding of the chemical vapor deposition of graphene. The randomized positioning of the graphene domains was then facilitated by dewetting the polymer film, followed by oxygen plasma etching. This approach yielded surfaces with randomly positioned and shaped graphene islands with varied numbers of layers and, therefore, Raman spectra. Raman mapping of surfaces resulted in multicolor images with a high encoding capacity. Advanced feature-matching algorithms were employed for the authentication of multicolor images. The use of two independent stochastic processes on a two-dimensional nanomaterial platform enables the creation of unique and complex surfaces that excessively challenge clonability.

Ultradurable Embedded Physically Unclonable Functions

“…(c) Flame and pressurized water stability tests of ultradurable embedded PUFs. (d) Comparison of the thermal stability of PUFs with the literature. ,,,,− …”

“…Motivated by the accelerating needs of encoded surfaces in anticounterfeiting and authentication, a diverse range of processes and materials have been recently explored for generation of PUFs. Quantum dots, − perovskite nanocrystals, luminescent materials, , plasmonic nanoparticles, − 2D materials, organic semiconductors, graphene, food-grade starch, self-wrinkling materials, , self-assembly of polymers, light-emitting organic molecules, electronic fingerprints, laser-induced carbonization, and polymeric particles are good examples to recent reports. The rich menu of materials proposed for PUF applications provides viable options for the vastly diverse needs of these applications.…”

Adlayer formation in low-pressure chemical vapor deposited graphene and its exploitation for creating PUF surfaces

“…The electropolishing step removes the surface oxide of Cu foils on both sides but leaves rough surface features, such as rolling marks, nearly unaffected on the back side, resulting in a significantly higher surface roughness on the back side than on the front side. 22) As shown in Figs. 1(a) and 1(b), the adlayer number density is significantly greater in graphene grown on the back side than that of the graphene grown on the front side of the foils.…”

“…The former decreases the growth rate, whereas the latter increases the etch rate, both of which decrease the adlayer number density. 22,27) The reaction of oxygen with hydrogen forms water vapor, which can also increase the etch rate by breaking the C-Cu bonds. 28) Hence, when the preannealing time is set to be sufficiently long and there are a large number of oxygen adsorbates on the Cu foil surfaces, the supersaturation level of the active carbon species can be kept sufficiently low to suppress adlayer formation.…”

Water-Molecule-Induced Reversible Fluorescence in a One-Dimensional Mn-Based Hybrid Halide for Anticounterfeiting and Digital Encryption–Decryption

“…Anticounterfeiting materials play an important role in information security. , Recently, organic–inorganic metal halides (OIMHs) have emerged as new-generation multifunctional materials due to their tunable structures and attractive optoelectronic properties. , For these OIMHs, individual inorganic units or metal halide clusters are completely surrounded and isolated by large organic cations to increase the distances between adjacent luminescent centers, reducing the concentration quenching effect − and resulting in unprecedented luminescence properties in various optical applications, such as white light-emitting diodes (WLEDs), X-ray detectors, scintillators, and photodetectors. − Among the previously reported OIMHs, some feature tunable optical characteristics like emission intensity or colors can occur due to the existence of a reversible transition for crystal structures when they are stimulated by mechanical forces, heat, moisture, light, or polar solvents. These tunable properties may have an effect on the optoelectronic performance of devices. − Moreover, with an interesting stimulus-responsive (SR) phenomenon, these susceptibilities are thought to have potential in water/temperature sensing and photodetection applications, − which inspire researchers to explore more diverse OIMHs with reversible transitions and investigate the mechanisms of tunable optical performance.…”