Ohmic Contacts to P–GaN Based on the Single–Walled Carbon Nanotubes

We have designed and verified a new structure for ohmic contacts to p-GaN, mainly for applications in light emitting devices based on a layer of single-walled carbon nanotubes (SWCNT) and metallic layers of Cr and Au, namely in configuration Au/Cr/SWCNT/p-GaN. The layer of carbon nanotubes was deposited on p-GaN by spraying a solution of synthesized SWCNTs, while the layers of Cr and Au were vapour deposited. The effects of the annealing temperature and time upon the electrical properties of Au/Cr/SWCNT/p-GaN contacts have been studied. It has been found that the contact structure provides a low resistivity ohmic contact after subsequent annealing in N2 ambient at 700 °C for 1 minute.