Diamond-like carbon film preparation and surface coatings of oxide superconducting and ferroelectric films Original Research Article

Diamond-like carbon (DLC) films as well as amorphous carbon films are investigated as possible passivation and environment protection for YBa2Cu2O7 − x (YBCO) oxide superconducting and Pb(ZrxTi1 − x)O3 (PZT) ferroelectric thin films. The pulsed laser deposition (PLD) technique was employed to prepare the perovskite oxide films of YBCO and PZT. These film surfaces were coated by the DLC films prepared using the excimer laser ablation method. Optimum deposition condition of the PLD process for the YBCO, PZT and DLC was investigated. In the case of DLC coatings, a graphite target was ablated using a KrF excimer laser of 2–9 J cm−2 in 200–800 mTorr hydrogen ambient gas. An optical band gap of 2.0 eV was attained on room temperature substrate and high quality superconductivity of the DLC coated YBCO films was kept over 1 month. The PZT film encapsulated by the DLC layer showed no degradation due to aging over 30 days.