14:15 〜 14:30
▲ [19p-W834-4] Self-Organized GaN Nanocolumns Grown on Silica Glass by RF-Molecular Beam Epitaxy
キーワード：GaN nanocolumn,fused silica
Nanocolumns (NCs) are widely known as a nanostructure having low dislocation density, low lattice strain and high light-extraction efficiency1). At the same time, fused silica, an amorphous form of quartz, is known as a material which possess high optical transparency (the light is transmitted with efficiency of at least 85 %) ranging from deep-ultraviolet to mid-infrared.
In this report, self-organized GaN NCs, employing no external catalyst, were successfully grown on fused silica glass substrates (thickness of 0.5 mm) by plasma-assisted molecular beam epitaxy. The dependence of NC radius and photoluminescence (PL) intensity on different growth conditions, namely growth temperature, Ga flux and N flow rate, was systematically investigated. The effect of the different growth conditions on the morphology and optical property of the NCs was studied by scanning electron microscopy (SEM) and PL measurement using He-Cd laser at room temperature, respectively. Si-doped GaN NCs were grown for 90 min with the substrate heater temperature of 1250 °C. The beam equivalent pressure of Ga, N2 flow rate and RF power were 2.5 x 10-4 Pa, 2.75 sccm and 450 W, respectively. In this condition, the NCs (radius of 68 nm and height of 1 μm) can be formed at a very high density (554 NCs/μm2) with the growth direction perpendicular relative to the substrate surface and yielded PL intensity of 5-6 times higher than the commercial GaN substrate grown via hydride vapor phase epitaxy. The findings of this work will pave the way toward the application of GaN NCs structures in light emitting diodes applications using amorphous silica glass as a substrate.
Reference: 1) Hiroaki Hayashi et al 2016 Nanotechnology 27 055302
In this report, self-organized GaN NCs, employing no external catalyst, were successfully grown on fused silica glass substrates (thickness of 0.5 mm) by plasma-assisted molecular beam epitaxy. The dependence of NC radius and photoluminescence (PL) intensity on different growth conditions, namely growth temperature, Ga flux and N flow rate, was systematically investigated. The effect of the different growth conditions on the morphology and optical property of the NCs was studied by scanning electron microscopy (SEM) and PL measurement using He-Cd laser at room temperature, respectively. Si-doped GaN NCs were grown for 90 min with the substrate heater temperature of 1250 °C. The beam equivalent pressure of Ga, N2 flow rate and RF power were 2.5 x 10-4 Pa, 2.75 sccm and 450 W, respectively. In this condition, the NCs (radius of 68 nm and height of 1 μm) can be formed at a very high density (554 NCs/μm2) with the growth direction perpendicular relative to the substrate surface and yielded PL intensity of 5-6 times higher than the commercial GaN substrate grown via hydride vapor phase epitaxy. The findings of this work will pave the way toward the application of GaN NCs structures in light emitting diodes applications using amorphous silica glass as a substrate.
Reference: 1) Hiroaki Hayashi et al 2016 Nanotechnology 27 055302