INVESTIGATION ABOUT THE INCORPORATION OF HYDROGEN INTO AMORPHOUS-CARBON

Amorphous carbon and hydrogen containing amorphous carbon films have b een prepared by evaporating polycrystalline graphite in hydrogen-free atmosphere (p(H2) < 10(-8) mbar) and in the presence of hydrogen at di fferent pressures (3 x 10(-4) -1.7 x 10(-2) mbar), respectively. After deposition, the films have been characterized by in situ photoelectro n spectroscopy. The composition of the gas phase during graphite evapo ration in the presence of hydrogen was measured with a quadrupole mass spectrometer. The gas phase data have been correlated to the hydrogen content in the film. It is found that hydrogen is incorporated prefer ably into amorphous carbon when already bound to carbon in the form of CH(x) (x = 1,2,3) in the gas phase. In addition, the bombardment of a growing amorphous carbon film with high energy hydrogen ions has turn ed out to be a quite effective means of incorporating hydrogen into a- C.