A study of substitutional nitrogen impurities in chemical vapor deposited diamond

Research was conducted to examine the fourfold coordinate nature of N in chemical vapor deposited (CVD) diamond and tetrahedral amorphous carbon (ta-C). Measurements were based on a combination of density-functional methods at several levels of approximation used on supercell and cluster models. Results reveal that when the Fermi level, Ef falls below A1, N doping charge is transferred to the available deeper lying states.