Vertically p-n-junctioned GaN nano-wire array diode fabricated on Si(111) using MOCVD

• Published in: Nanoscale 2013-01, Vol.5 (7), p.2959-2966
• Main Authors: Park, Ji-Hyeon, Kim, Min-Hee, Kissinger, Suthan, Lee, Cheul-Ro
• Format: Article
• Language: English
• Subjects: Arrays; Diodes; Flow rate; Gallium nitrides; Magnesium; Nanocomposites; Nanomaterials; Nanostructure
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c3nr34245j

We demonstrate the fabrication of n-GaN:Si/p-GaN:Mg nanowire arrays on (111) silicon substrate by metal organic chemical vapor deposition (MOCVD) method .The nanowires were grown by a newly developed two-step growth process. The diameter of as-grown nanowires ranges from 300-400 nm with a density of 6-7 × 10 7 cm −2 . The p- and n-type doping of the nanowires is achieved with Mg and Si dopant species. Structural characterization by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicates that the nanowires are relatively defect-free. The room-temperature photoluminescence emission with a strong peak at 370 nm indicates that the n-GaN:Si/p-GaN:Mg nanowire arrays have potential application in light-emitting nanodevices. The cathodoluminscence (CL) spectrum clearly shows a distinct optical transition of GaN nanodiodes. The nano-n-GaN:Si/p-GaN:Mg diodes were further completed using a sputter coating approach to deposit Au/Ni metal contacts. The polysilazane filler has been etched by a wet chemical etching process. The n-GaN:Si/p-GaN:Mg nanowire diode was fabricated for different Mg source flow rates. The current-voltage ( I - V ) measurements reveal excellent rectifying properties with an obvious turn-on voltage at 1.6 V for a Mg flow rate of 5 sccm (standard cubic centimeters per minute). A vertically oriented p-n-junction GaN nanowire array diode is fabricated on Si(111) by a newly developed two-step growth process.