Investigation of the effect of the doping order in GaN nanowire p-n junctions grown by molecularbeam epitaxy

• Published in: Nanotechnology 2020-11
• Main Authors: Saket, Omar, Wang, Junkang, Amador-Mendez, Nuno, Morassi, Martina, Kunti, Arup, Bayle, Fabien, Collin, Stéphane, Jollivet, Arnaud, Babichev, Andrey, Sodhi, Tanbir, Harmand, Jean-Christophe, Julien, François H, Gogneau, Noëlle, Tchernycheva, Maria
• Format: Article
• Language: English
• Subjects: Engineering Sciences; Materials; Micro and nanotechnologies; Microelectronics; Optics; Photonic
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/abc91a

We analyse the electrical and optical propreties of single GaN nanowire p-n junctions grown by plasma-assisted molecular-beam epitaxy using magnesium and silicon as doping sources. Different junction architectures having either a n-base or a p-base structure are compared using optical and electrical analyses. Electron-beam induced current microscopy of the nanowires shows that in the case of a n-base p-n junction the parasitic radial growth enhanced by the Mg doping leads to a mixed axial-radial behavior with strong wire-to-wire fluctuations of the junction position and shape. By reverting the doping order p-base p-n junctions with a purely axial well-defined structure and a low wire-to-wire dispersion are achieved. The good optical quality of the top n nanowire segment grown on a p-doped stem is preserved. A hole concentration in the p-doped segment exceeding 10 18 cm-3 was extracted from electron beam induced current mapping and photoluminescence analyses. This high concentration is reached without degrading the nanowire morphology.