An Introduction to Security Based on Physical Disorder.- An Introduction to Semiconductors and Quantum Confinement.- Sample Preparation and Experimental Techniques.- Unique Identification with Resonant Tunneling Diodes.- Langmuir-Blodgett Deposition of 2D Materials for Unique Identification.- Building Optoelectronic Heterostructures with the Langmuir-Blodgett Technique.- Conclusions and Future Work.