Comparison of the effect of boron and nitrogen incorporation on the nucleation behavior and electron-field-emission properties of chemical-vapor-deposited diamond films

Effect of boron (or nitrogen) doping on the nucleation behavior of chemical-vapor-deposited diamond films was investigated. It is observed that inclusion of B(OCH3)3 species in gases markedly enhances, whereas addition of (NH3)2CO species pronouncedly retards the nucleation of diamonds. Raman spectroscopic analyses reveal that the probable mechanism is the formation of boron–carbon clusters due to boron incorporation. While the boron (or nitrogen) species incorporated insignificantly modify the microstructure, these dopants markedly alter the electron-field-emission behavior of the diamond films. The field-emission properties are optimized for films grown with B(OCH3)3=2 sccm [or (NH3)2CO=6 sccm]. The nitrogen-doped films exhibit significantly superior electron-field-emission capacity to the boron-doped films, even though the latter possess much lower electrical resistivity [viz. (Je)n=1020 μA/cm2, (ρ)n=76 mΩ cm and (Je)b=360 μA/cm2, (ρ)b=2.1 mΩ cm].