Study of emission centers in amorphous carbon (a-C:H) by field electron and field desorption microscopy

An amorphous hydrogenated carbon (a-C:H) film on tungsten (W) has been studied by field emission (FE) methods (field electron and field desorption microscopy). Carbon films (a-C:H) have been grown by dc reactive magnetron sputtering of a graphite target in an argon–hydrogen plasma. An original method of field desorption microscopy in continuous mode, based on adsorption of alkaline atoms of Cs on a substrate under study, has been applied to obtain field electron and field desorption images of the sample surface. Comparison of the field electron and field desorption images of the a-C:H film shows that graphite nanoclusters are formed in the dielectric medium of amorphous carbon. Strong electron emission originating from graphite nanoclusters embedded in the dielectric matrix has threshold nature. A combination of the above methods of FE microscopy is a very promising experimental technique for investigation of emission centers in carbon-based nanocomposites.