The structure, interfacial nanochemistry, and electrical properties of sol-gel derived Pb(Zr0.3Ti0.7)O-3 or PZT (30/70) thin films on metal-organic chemical vapor deposited (0001) GaN/sapphire substrates are reported. The X-ray diffraction analysis confirmed a phase-pure and highly oriented (111) PZT and Rutherford backscattering spectroscopy was used to ascertain the Zr/Ti ratio. The secondary ion mass spectrometry depth profile and electron energy loss spectroscopy with high energy and spatial resolution indicated a chemically sharp PZT/GaN interface with insignificant interdiffusion between Pb, Zr, or Ti in PZT and Ga and N in GaN. The lower capacitance density (C/A=0.35 mu F/cm(2)) and asymmetrical polarization (P similar to 4 mu C/cm(2)) hysteresis loops of PZT in Pt/PZT/GaN or metal-ferroelectric-semi conductor configuration were attributed to the high depolarization field (E-depol) within PZT. In contrast, PZT in Pt/PZT/Ru/GaN or metal-ferroelectric-metal configuration exhibited high capacitance density (C/A=1.25 PF/cm(2)) and polarization (P similar to 30 mu C/cm(2)). (c) 2005 Elsevier B.V. All rights reserved.