Single Wall Carbon Nanotubes for p-Type Ohmic Contacts to GaN Light-Emitting Diodes

Homogeneous films of pure single wall carbon nanotubes (SWNTs) sufficiently thin to be optically transparent in the visible range of the spectrum were employed as p-Ohmic contacts on GaN−InGaN quantum-well light-emitting diodes. The specific contact resistance of the SWNT films on the p-GaN was 1.1 × 10 -2 Ω cm 2 after annealing at 700 °C for 60 s under N 2, which was a factor of 3 lower than standard Ni/Au contacts on the same p-GaN. The SWNT-contacted LEDs showed bright blue emission centered at 434 nm and demonstrate that the SWNT films provide a new class of electrically conducting, p-type, transparent electrode for use with photonic devices.