Advanced diamond/sp(2)-bonded carbon nanocomposite materials as low threshold field electron emitters

Field electron emission from different types of diamond/sp(2)-bonded carbon nanocomposite materials including diamond/pyrocarbon composites and CVD di amond films is considered as a function of their structure. Uniform emissio n at low threshold fields of 1-3 V/mum was observed for samples with nanoco mposite structure, where diamond is combined with a large amount of sp(2)-b onded carbon phase. In contrast, the samples with a predominance of diamond or bulk graphite phases emit poorly. Special STM study of the microscopic properties of the emission centers shows that emitted electrons escape from diamond/sp(2-)bonded carbon interfaces and thin conducting layers with red uced values of the work function. The mechanisms of the low-threshold emiss ion including local field enhancement and decrease of the tunneling barrier are considered. To describe the emission from the nanocomposite samples, i t is suggested that one take into account quantum well effects on thin carb on nanolayers and at insulator/graphite interfaces.