Epitaxy and the characterization of core-shell GaN columnar light-emitting Diodes


Three dimensional (3D) GaN nanorods or microcolumns have recently gained increased attention for applications in optoelectronic and electronic devices. This is due to the low defect density and reduced influence of lattice and thermal mismatch to the substrate. In comparison to conventional planar light emitting diodes (LEDs), the active region of 3D column LED systems can be much larger when using a core-shell geometry with high aspect ratio. A further advantage is that the InGaN/GaN multi quantum wells (MQWs) mainly grow defect free on non-polar m-plane side walls.

N-polar and Ga-polar n-doped GaN columns have been successfully realized on patterned SiOx/sapphire and SiOx/GaN/sapphire, respectively, employing a conventional continuous growth mode by metal organic vapor phase epitaxy (MOVPE). The growth mechanism will be discussed in details. InGaN/GaN MQWs with a p-doped GaN cap have been grown on Ga-polar and N-polar GaN columns in a core-shell geometry. The optical characters of core-shell LEDs have been investigated by CL and PL.

TU Braunschweig
Ph.D. student: