Observation of ferroelectric domain structures by secondary-electron microscopy in as-grown KTiOPO4crystals

Abstract

Ferroelectric domain structures of as-grown KTiOPO 4 crystals are observed on polished polar surfaces by the scanning secondary-electron microscopy ͑SEM͒ method. The results demonstrate a different contrast origin for domain boundaries and domains themselves. It is shown that the electron-beam irradiation in SEM causes a local heating of the ferroelectric crystal. Detailed calculations of the effects involved allow to assume that pyroelectric potentials induced by heating are opposite in sign for C ϩ and C Ϫ domains which is the main reason for the domain contrast. Domain boundaries are revealed due to the converse piezoelectric effect and the corresponding crystal deformations of ferroelectric domains are induced by electron-beam charging.

Polarization-dependent electron affinity of LiNbO3 surfaces

“…Alternatively, scanning electron microscopy (SEM) has been employed for the observation of ferroelectric domain structures. 7,8 The SEM domain contrast was ascribed to asymmetric secondary electron emission from opposite domains due to the pyroelectric potential difference induced by electron beam heating 7 or due to a work function difference induced by surface adsorption. 8 It is worth noting that different groups observed opposite SEM contrast for domains of the same polarity and that the proposed models did not reconcile these contradictory results.…”

“…The PEEM images were obtained with photon energies from 4-6.2 eV with an energy full width at half maximum of ϳ0.1 eV. 7 To verify domain polarity, complementary PFM imaging of the sample has been performed. a)…”

Gamma irradiation-induced absorption in single-domain and periodically-poled KTiOPO_4 and Rb:KTiOPO_4

“…Part of the secondary electrons will have low enough energy (electron work function in KTP is about 4.5 eV [45]) to be bound in the valence orbitals of the TiO 6 structural groups, which were ionized before by the gamma radiation or the Compton electrons. In KTP the electronic states of these structural groups are mostly contributing to the states at top of the valence band and at the bottom of the conduction band [46].…”

Ultrathin Ferroelectric Films: Growth, Characterization, Physics and Applications

“…A scanning electron acoustic microscopy (SEAM), which is integrated with electron-optic techniques, electron audio techniques, and piezoelectric sensors, has been employed for damage-free and high-resolution imaging of domains [234]. With the development of SEM techniques, many studies have been successfully established on ferroelectric domain observation through SEM techniques, such as PTO, PZT, BTO, Bi 4 Ti 3 O 12 , LiTaO 3 , KTiOPO 4 (KTP) [235,236,237], etc .…”