Comparison of field electron emission from DLC films produced by four different deposition techniques

Diamond-like carbon (DLC) films produced by ion beam, laser-arc, r.f.-plasma deposition and magnetron sputtering were characterized on the field electron emission properties (thresholds, hysteresis behaviour, stability, homogeneity). The best samples showed electron emission at fields of 4-20 V mu m(-1). Correlations between emission properties and film hardness, Raman spectra, optical band gap,. sp3-bonded carbon content and electroconductivity were found. A specially designed high vacuum scanning tunneling-field emission microscope was used for simultaneous mapping of film morphology, work function and local field emission intensity. Correlations were observed between emission centres location and work function minima. Factors that improve the field electron emission from DLC films are discussed.