Abstract
Graphene sheets were employed as a diffusion barrier to form highly reliable ohmic contacts to N-polar n-GaN for high-power vertical-configuration LEDs (VLEDs). Before annealing, both Ti/Al and Ti/graphene/Al contacts exhibit ohmic behavior. After annealing at 250 °C, unlike the Ti/Al contact, the Ti/graphene/Al contacts remain ohmic with a contact resistivity of 7.5 × 10-4Ωcm2. Secondary ion mass spectroscopy (SIMS) results show that the graphene sheets serve as a barrier to the outdiffusion of Ga atoms into the electrode. On the basis of SIMS and X-ray photoemission spectroscopy results, the ohmic and degradation behaviors of the Ti-based contacts are described and discussed.
Original language | English |
---|---|
Article number | 046501 |
Journal | Applied Physics Express |
Volume | 7 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2014 Apr |
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy(all)