Thursday, September 17, 2009

"MATERIALS: Graphene mixes it up with GaAs"

Carbon promises to replace silicon at the end of the semiconductor roadmap, but what about gallium arsenide which is already used instead of silicon for high-performance applications such as radio frequency (RF) power amplifiers (PAs). Now researchers have succeeded in combining graphene and gallium arsenide into a new super-material. Look for hybrid graphene-on-GaAs in discrete devices within five years. R.C.J.

Pure carbon atoms based on depositing graphene on gallium arsenide wafers could yield the next generation of high performance semiconductors, according to German researchers. Investigators at the Physikalisch-Technische Bundesanstalt (Braunschweig, Germany) recently claimed to have imaged graphene on the surface of a GaAs wafer for the first time using an optical microscope. Nearly invisible single-carbon atom layers can be made visible using a normal optical microscope if the support layer is designed as an anti-reflection filter. Single-layer graphene is identified inside the marked areas. GaAs is widely used in semiconductors that must outperform silicon chips, especially in RF applications where the wavelengths are too short for CMOS. Future carbon-based chips will likely use layers of crystalline carbon--graphene--to outperform silicon, prompting the German researchers to begin investigating ways of depositing graphene on GaAs to achieve a hybrid material with advanced properties.