Growth and characterization of Sm3+-substituted PZT thin films

We report a systematic study on growth of 2% and 4% Samarium (Sm) substituted lead zirconate titanate (PZT) thin films (with molar ratio of Zr:Ti::65/35) by sol gel technique on Pt/Si <1 0 0> and Pt/Si <1 1 1> substrates. XRD analysis show single phase for all films. Surface morphology was studied using atomic force microscope (AFM). A metal/ferroelectric/metal (MFM) structure was formed by depositing gold electrode on top of the film for electrical measurements (I-V (current vs voltage), C-V (capacitance vs voltage), P-E (polarization vs electric field)). The films show well-defined ferroelectric behaviour for both compositions (2% and 4% Sm-substituted PZT). I-V measurements show a compositional shift along -ve (negative) voltage axis. To obtain optical band gap, films were deposited on fused quartz and transmittance measurements were performed. Optical band gap was calculated from (αhυ)2 vs hυ graph (where α is the extinction coefficient, h the planck's constant and υ the frequency of light). The results are discussed