InGaN/GaN quantum-well nanocolumn crystals on pillared Si substrate with InN as interlayer

Nanocolumn InGaN/GaN crystals were deposited on micropillared Si substrate by molecular beam epitaxy. Low-temperature InN was used as interlayer. With enough free space, the column crystals grew around all the surface plane of the Si pillars and formed InGaN/GaN quantum-well flower structure. The QW crystals are about 100 nm in diameter and 1.1-1.4 μm in length. Raman spectra measurement of the fower structure shows that E₂ mode peak line observed at 567.28 cm^-1. Photoluminescence measurement indicates a room temperature PL peak position of 620 nm and two peak positions of 404 nm and 519 nm at temperature 15 K. Hg lamp excited photoluminescence demonstrated a clear fluorescence distribution in the flower structure and much stronger emission compared with the quantum-well crystals on the flat Si substrate.