Fabrication of periodically ordered diamond nanostructures by microsphere lithography

Structured diamond films are required for several uses as photonic crystals, (bio-) sensors, biomedicine, etc. Often, these uses require fabrication of nano-sized features with the assistance of lithographic techniques. In this paper, we demonstrate the growth of diamond structures well ordered in periodic arrays. The technological process starts with ultrasonic seeding of Si substrates by ultra-dispersed detonation diamond nanoparticles. Then, a monolayer of polystyrene microspheres (PS) is deposited on seeded Si substrates by Langmuir–Blodgett method. The primary diameter of PS varies from 253 to 940 nm. The self-assembled PS are employed as a mechanical mask for reactive ion etching of the seeding layer via reducing the PS diameter down. The seeding structures remained under reduced PS were used for growing periodically ordered diamond arrays by microwave plasma-assisted chemical vapor deposition from a hydrogen rich gas mixture. Cross-section SEM images reveal that the diameter and size of the formed diamond structures increase both in vertical and lateral direction. At a certain deposition time, the structures start to coalesce into a continuous layer.