Nanoscale shuffling in a template-assisted self-assembly of binary colloidal particles

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Information Security

Background:

• Developing secure and tamper-proof identification and encryption methods is crucial for modern security.
• Nanoscale materials offer unique properties for advanced technological applications.
• Random bit sequences are fundamental for cryptography and data security.

Purpose of the Study:

• To fabricate a square lattice array of sub-micrometer fluorescent polystyrene particles.
• To generate a one-dimensional bit sequence from the particle array.
• To evaluate the randomness and potential applications of the particle array for identification and encryption.

Main Methods:

• Fabrication of a silicon substrate with pits using electron beam lithography.
• Embedding red and green fluorescent polystyrene particles into pits via controlled drying of an aqueous suspension.
• Indexing particles (0 for red, 1 for green) to create a bit sequence and statistical analysis using the FIPS 140-2 test suite.

Main Results:

• Successfully created a square lattice array of red and green fluorescent particles.
• Generated one-dimensional bit sequences with no detectable non-randomness, validated by FIPS 140-2 statistical tests.
• Demonstrated the unpredictability and irreproducibility of particle distribution, yielding a vast number of possible patterns.

Conclusions:

• The simple fabrication process yields a highly random and unpredictable particle array.
• The fluorescent signal is stable under various conditions, making it suitable for diverse applications.
• The particle array is a promising candidate for nanoscale identification tags and one-time pad encryption tips.