Jie Sun, Niclas Lindvall, August Yurgens, Mikroteknologi och Nanovetenskap, Chalmers Tekniska Högskola AB, Göteborg 41296, Sweden
We also grow graphene directly on insulators without metal catalysts in CVD.1-9 The graphene is nanocrystalline, large area and uniform. Despite the lower mobility (40 cm2/(Vs)) compared to catalyzed graphene, its transparency (97%) and conductivity (1-a few kΩ/□ without intentional doping) is similar to standard graphene, making such transfer-free graphene very promising in applications of transparent electronics and molecular electronics. The graphene can be grown on arbitrary dielectrics that withstand high temperature. We have proposed a novel noncatalytic CVD (as opposed to catalytic graphene CVD on metals) mechanism to explain our experimental findings.3 Both the catalyzed and noncatalyzed graphene can be suspended, promising for nanoelectromechanical systems (NEMS).7,8
The graphene finds its applications in GaN optoelectronics. GaN compounds are widely used in light emitting diodes (LEDs) covering the spectrum from yellow to ultraviolet. We first study ordered and dense GaN light emitting nanorods with graphene grown by CVD as suspended transparent electrodes.11 As the substitute of indium tin oxide (ITO), the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes, mainly due to the much more enlarged light emitting areas.11
1. IEEE Transactions on Nanotechnology, 11 (2012) 255.
2. Applied Physics Letters, 98 (2011) 252107.
3. Applied Physics Letters, 100 (2012) 022102.
4. Journal of Applied Physics, 111 (2012) 044103.
5. Carbon, 50 (2012) 1987.
6. Advanced Materials, 24 (2012) 1576.
7. Proceedings of IEEE NEMS 2012, p. 11.
8. Proceedings of IEEE NEMS 2012, p. 19.
9. Nano Letters, 12 (2012) 5074.
10. Applied Physics Letters, 102 (2013) 022101.
11. Applied Physics Letters, 103, (2013) 222105.
Collaboration for joint projects is warmly welcome (e.g. EU and national funds application). Contacts: Jie.firstname.lastname@example.org