Growth and optical properties on formation of self-assembled GaN nanorod grown on Si(111) substrates

We have investigated the growth condition and optical properties on the formation of dislocation free vertical GaN nanorod grown on Si(111) substrates by molecular beam epitaxy. The hexagonal shape nanorod with lateral dimension from 10 nm to 350 nm is fully relaxed from lattice strain. We have found that the hexagonal nanorod can be formed on Si substrate, not only in N-rich condition but also even in a Ga-rich condition, when it is formed without buffer layer at high growth temperatures. They are fully relaxed and have a very good crystal quality characterized by extremely strong and narrow photoluminescence excitonic lines near 3.47 eV.