Growth of GaN films on CoGa(001): An EELS and AES study

The formation and properties of ultra-thin GaN films were investigated by means of high-resolution electron energy-loss spectroscopy (EELS) and Auger electron spectroscopy (AES). Using the intermetallic alloy CoGa as the substrate material, GaN can be prepared on the (001) surface upon adsorption of ammonia at 80 K and subsequent thermal decomposition. Ultra-thin GaN films were grown by repeated cycles of ammonia adsorption and heating to 650 K. The GaN films show an FK mode at 695 cm(-1), agreement with calculated spectra based on IR parameters. The electronic energy gap is determined to be E-g approximate to 3.5 eV.