Structural and electrical properties of pulsed laser deposited BaPbO₃ conductive thin films and its effect on the ferroelectric properties of PbZr_0.52Ti_0.48O₃ /BaPbO₃ heterostructures

ABSTRACT

BaPbO₃ (BPO) thin films of different thickness were deposited by pulsed laser deposition on p type Si/SiO₂ substrates. The influence of film thickness on the structural and electrical properties is studied. It is found that the BPO thin films of 300 nm has good crystallinity and grain size of 21nm. The carrier mobility increases with film thickness for films above 150 nm due to the ordered structure resulting in large grain size and small number of boundaries which enhances charge transport.

The effect of BPO film thickness on the ferroelectric properties of Pb(Zr_0.52Ti_0.48)O₃ (PZT) thin films grown over BPO electrode were also investigated. Stress analysis on the thin films was carried out to investigate the dependence of BPO thickness on the ferroelectric properties of PZT. The mean grain size of PZT obtained by the Williamson – Hall Plots are 33, 45, 57 and 39 nm with increasing BPO film thickness. It was found that the P_r values of PZT film deposited over BPO of thickness 225 nm is relatively large with low Ec. It is observed that stress and grain size effects have a competing effect. Larger grain size possess a decreased grain boundary density, which reduces the probability of space charge trapping at grain boundaries and facilitate effective domain mobility which result in the improvement of ferroelectric properties.

KEYWORDS:

• Thin film
• PLD
• thickness
• stress analysis
• PZT/BaPbO₃ heterostructures