Combination of synchrotron ellipsometry and table-top optical measurements for determination of band structure of DLC films

Model of the DLC band structure that took into account valence to conduction band transitions, π → π⁎ and σ → σ⁎, and valence to extended states transitions σ → ξ⁎ was confirmed by using the synchrotron ellipsometry at BESSY II in the range 5-30 eV combined with table-top ellipsometry and spectrophotometry in UV-IR range. The range up to 30 eV covered all the transitions from valence to conduction bands because the maximum energy transition of π → π⁎ and σ → σ⁎ were 9.03 and 28.1 eV, respectively. The band gaps of these transitions were 0.75 and 4.74 eV, respectively.