Researchers have carved out wonderful silicon nanostructures using excimer laser, a type of ultraviolet laser1.
Known as krypton fluoride laser (KFr laser), the laser's irradiation forms nanopores, nanoparticles, and nanowires of silicon. These silicon nanostructures could help design tiny electronic devices.
An excimer laser is commonly used in eye surgery and semiconductor manufacturing. The laser typically uses a combination of inert gas (argon, krypton, or xenon) and a reactive gas (fluorine or chlorine). The plus point of excimer lasers is that they can remove exceptionally fine layers of surface material with almost no heating or alteration of the remainder material.
To tap this potential, the researchers prepared krypton fluoride laser and irradiated the silicon surface. At low energy, laser irradiation resulted in nanopores measuring between 40 and 60 nm and nanoparticles having diameter between 40 and 80 nm. At higher energy, laser irradiation formed silicon nanowires of 200 nm diameter and closely spaced silicon nanograins of 100-150 nm diameter.
After 100 shots, the energy-packed laser caused a transition of the silicon surface to randomly oriented nanocrystalline state.
The research is significant as silicon nanocrystals and nanostructures might have applications in various fields such as photonics (electroluminescence diode and microcavity), electronics (single-electron device, spin transistor, non-volatile memory, and ballistic electron emitter), acoustics and biology.
