Highly textured Pb(Zr_0.3Ti_0.7)O₃ thin films on GaN/sapphire by metalorganic chemical vapor deposition

Abstract

Highly (111) textured Pb(Zr 0.3 Ti 0.7 )O 3 (PZT 30/70) films were deposited on (0001) GaN/sapphire substrates using liquid-source metalorganic chemical vapor deposition (MOCVD) technique at 520°C and 80 nm/min. The crystallinity of as-deposited PZT films and the structure of PZT/GaN interface were evaluated by x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM), respectively. Mitigated by geometric epitaxy and strain energy minimization, the orientation relationships of PZT on epi-GaN, determined using x-ray pole figure and selected area diffraction pattern, were as follows: out-of-plane alignment of [111] PZT//[0001] GaN, and orthogonal in-plane alignments of [112] PZT//[1100] GaN (zone axes) and [110] PZT//[1120]GaN. The nanochemistry of the PZT (150nm)/GaN interface, studied using analytical TEM, indicated a chemically sharp interface with interdiffusion limited to a region below 5 nm. The properties of as-deposited PZT on GaN by MOCVD are briefly compared with PZT by sol-gel processing, radio-frequency sputtering, and pulsed laser deposition.

Structural and electrical properties of Pb(Zr,Ti)O3 grown on (0001) GaN using a double PbTiO3∕PbO bridge layer

“…Therefore, the in-plane epitaxial relationships can be established as follows: PZT͓112͔ ʈ GaN͓1100͔ and PZT͓110͔ ʈ GaN͓1120͔. The same epitaxial relationships have been reported by Dey et al 15 for PZT films grown on GaN ͑0001͒ by MOCVD.…”

Ferroelectric Pb(Zr,Ti)O3 epitaxial layers on GaAs

“…Most of these studies report on polycrystalline or textured PZT thin layers deposited by sol-gel or magnetron sputtering. 10,11,14 With those layers, RF devices, 12 MEMS, 13 and optoelectronic devices 14 have been investigated. Very recently, the fabrication of single-crystalline PZT layers on MgO/GaN templates has been reported.…”

Inverted‐Structural Self‐Powered Gan/PZT/ITO UV Photodetector Enhanced by Ferroelectric Modulation

“…[43] More importantly, PZT demonstrated a small lattice mismatch with GaN, [44] and by leveraging the polarity control of GaN, highly crystalline PZT films predominantly oriented along the (111) direction can be fabricated, resulting in a large spontaneous polarization. [45][46][47] Moreover, both PZT and GaN exhibit high breakdown voltages, [48,49] creating favorable conditions for the generation of a strong remnant polarization by high-voltage polarization. Therefore, the combination of PZT and GaN holds promise for constructing high-performance self-powered UV photodetectors.…”