Structural and optical properties of Eu-doped GaN nanocolumns on (111) Si substrates grown by RF-plasma-assisted molecular beam epitaxy

Abstract

Eu-doped GaN (GaN:Eu) shows a sharp line emission and the thermal stability of the emission wavelength. To improve their optical properties, GaN:Eu nanocolumns were grown on GaN nanocolumn platforms with high crystalline quality by RF-plasma-assisted molecular beam epitaxy. The GaN:Eu growth temperature strongly affected the nancolumn configuration. Although a high growth temperature of more than 700 °C enhanced lateral growth, a low growth temperature of 600 °C led to independent GaN:Eu nanocolumns. Although it was revealed that an increase in Eu concentration brought about polycrystalline growth, the optically active site concentration increased with increasing Eu concentration without concentration quenching, which suggests that the nanocolumn crystal is a valuable material for developing the novel optical devices utilizing GaN:Eu.