Buffer controlled GaN nanorods growth on Si(111) substrates by plasma-assisted molecular beam epitaxy

Abstract

Size, shape, and density of self-assembled GaN nanorods grown on Si͑111͒ substrates by plasma-assisted molecular beam epitaxy were successfully controlled by inserting a GaN buffer layer. The structure of the GaN buffer layer plays a vital role in the nanorod growth. Only a broken buffer layer with a suitable opening size can grow nanorods. Evolution of the nanorod is traced to the initial growth stage. Crystal seed grown at the wall of the opening in the buffer layer initiates the beginning of the nanorod, and a self-catalytic vapor-liquid-solid process, triggered by the nanocapillary condensation effect, enhances the GaN nanorod growth. Furthermore, the nanorod density can be largely controlled by using the beam equivalent pressure of the N / Ga ratio. Other GaN nanostructures grown at different growth conditions are also discussed in details.

Built-in surface electric field, piezoelectricity and photoelastic effect in GaN nanorods for nanophotonic devices

“…The average diameter of the studied nanorods was about 50 nm with a length of about 0.5 μm, and the average density of the nanorods was ∼10 7 cm −2 . A detailed distribution of the nanorods has been shown in our previous report [18]. Other detailed properties with various growth parameters can also be found elsewhere [10,18,19].…”

Luminescence characterization of InGaN/GaN vertical heterostructures grown on GaN nanocolumns

“…The spontaneous growth of c-axis oriented GaN nanocolumns on Si(111) by MBE using high substrate temperatures and N-rich conditions has been studied by several groups [1,[4][5][6][7][8].…”

Micro-Raman spectroscopy of a single freestanding GaN nanorod grown by molecular beam epitaxy

“…10 In this work, we report the results of polarized micro-Raman spectroscopy study of a single freestanding, high-quality GaN nanorod with no other peaks except ϳ3.4 eV transition in photoluminescence measurement, which was grown by plasma-assisted molecular beam epitaxy on Si͑111͒ substrates. 2,11 These GaN nanorods are all vertically aligned to the substrate, with the c axis along the growth direction, and show well-faceted hexagonal shape. To elucidate the phonon behaviors in nanorods, the dependence of the Raman shift on the angle between the laser polarization direction and the rod c axis is investigated.…”