X-ray data of the PZT, PLT, and doped PZT samples: PZT56 (a) as sputter grown and (b) annealed, and PZT82 (c) as sputter grown and (d) annealed. Others are grown by sol-gel method: (e) PZT20, (f) PNZT, (g) PLZT, and (h) PLT. Pv and Pr designate perovskite and pyrochlore phases, respectively.
Pseudodielectric functions in the spectral range of : (a) , , 0.56, 0.82, and (b) PNZT, PLZT, and PLT. The three band-gap peaks are identified as , , and , respectively.
(solid lines) measured at angle of incidence and their curve fits (dotted lines) using layer modeling for (, 0.56, 0.82), PNZT, PLZT, and PLT.
Fitted dielectric function of the PZT layers in the spectral range of : (a) PZTs and (b) PNZT, PLZT, and PLT.
Plot of the second derivative of dielectric functions and their fits in the NIR-VIS-UV spectral range. The fitted band-gap energies and are marked with arrows.
Plot of the second derivative of dielectric functions and their fits in the DUV spectral range for PZT20, PNZT, PLZT, and PLT grown on platinized silicon. The fitted band-gap energy is marked with an arrow.
Plot of band-gap energies for PZTs, PLT, and doped PZTs fitted (our own) and from literature. Filled symbols are from our data of spectroscopic elipsometry (SE), and other symbols are unfilled circle [Peng et al. (Ref. 6)], unfilled triangle [Yang et al. (Ref. 7)], unfilled rectangle [Zametin (Ref. 25)], and half-filled circle [Moret et al. (Ref. 8)].
Calculated band structure of (a) and (b) . The energy zero is at the top of the valence band.
Calculated band-gap energies of as a function of composition. The lines assume linear interpolation between the two end-point compounds, and .
Calculated absorption spectra for and .
Thickness and volume fraction of void in surface roughness layer. The thickness of the main layer was determined by ellipsometry. AFM-measured roughness and the main x-ray peaks are listed with crystal phase (: perovskite, : pyrochlore), substrate, and growth method.
Band-gap energies estimated by POC and SCP models. The error bars are within 95% reliabilities.
Calculated optical transition-matrix element squared for several band-edge transitions in PTO and PZO.
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