Temperature- and electrode-dependent leakage current behaviour of pulsed laser deposited Ba(Ti0.85Sn0.15)O3 thin films

The leakage behaviour of Ba(Ti0.5Sn0.15)O3 (BTS) thin films deposited by pulsed laser deposition has been studied. Two kinds of materials, Pt and LaNiO3 (LNO), are used as bottom electrodes to investigate their influences on conduction mechanisms. It is found that the leakage of the BTS thin films is strongly related to the deposition temperature and electrode materials. For the Pt/BTS/LNO structure, the leakage current shows bulk-limited space-charge-limited current (SCLC) behaviour at a positive bias while interface-limited Fowler–Nordheim tunnelling at a negative bias. On the other hand, for the Pt/BTS/Pt structure, the leakage current shows a symmetric characteristic at both positive and negative biases. The conduction mechanism is controlled mainly by the bulk-limited SCLC and/or Poole–Frenkel emission, which is operative depending on the temperature and electric field.