Improving optical performance of GaN nanowires grown by selective area growth homoepitaxy: Influence of substrate and nanowire dimensions
- ISOM-ETSIT, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)
- Departamento de Química Inorgánica, Facultad de Químicas, Universidad Complutense (UCM), CEI Moncloa, 28040 Madrid (Spain)
Series of GaN nanowires (NW) with controlled diameters (160–500 nm) and heights (420–1100 nm) were homoepitaxially grown on three different templates: GaN/Si(111), GaN/AlN/Si(111), and GaN/sapphire(0001). Transmission electron microscopy reveals a strong influence of the NW diameter on dislocation filtering effect, whereas photoluminescence measurements further relate this effect to the GaN NWs near-bandgap emission efficiency. Although the templates' quality has some effects on the GaN NWs optical and structural properties, the NW diameter reduction drives the dislocation filtering effect to the point where a poor GaN template quality becomes negligible. Thus, by a proper optimization of the homoepitaxial GaN NWs growth, the propagation of dislocations into the NWs can be greatly prevented, leading to an exceptional crystal quality and a total dominance of the near-bandgap emission over sub-bandgap, defect-related lines, such as basal stacking faults and so called unknown exciton (UX) emission. In addition, a correlation between the presence of polarity inversion domain boundaries and the UX emission lines around 3.45 eV is established.
- OSTI ID:
- 22590828
- Journal Information:
- Applied Physics Letters, Vol. 108, Issue 25; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pendeo-epitaxial growth and characterization of GaN and related materials on 6H-SiC(0001) and Si(111) substrates
Influence of the adatom diffusion on selective growth of GaN nanowire regular arrays