Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method

Thick KNbO₃ films deposited by ultrasonic-assisted hydrothermal method

“…On the other hand, a too long period of ultrasonic irradiation resulted in thinner films as indicated by films (d) and (e). This tendency was also confirmed for the case of PZT deposition [8]. It is considered that the ultrasonic irradiation promotes the nucleation process but does not promote the crystal growth process.…”

“…In our previous study concerning the deposition of the thick PZT film, it was clarified that there is an optimum ultrasonic irradiation time for obtaining large thickness [8]. We examined the relationship between the thickness of the KNbO 3 film and the period of ultrasonic irradiation.…”

“…In this study, thick potassium niobate (KNbO 3 ) films were investigated, which are required for medical transducers and micro actuators. To fabricate such films, we introduced an ultrasonic-assisted hydrothermal method [7][8][9][10][11].…”

“…However, it has a long reaction time and repeated deposition has been required for thicker films [12,13]. To overcome this problem, we developed an ultrasonic-assisted hydrothermal method [7][8][9][10][11] to obtain thicker films. Upon ultrasonic irradiation, cavitation is generated, which is effective for promoting the hydrothermal reaction [8].…”

“…To overcome this problem, we developed an ultrasonic-assisted hydrothermal method [7][8][9][10][11] to obtain thicker films. Upon ultrasonic irradiation, cavitation is generated, which is effective for promoting the hydrothermal reaction [8]. So far, we have confirmed the effect of ultrasonic irradiation on increasing the thickness of PZT films [7,8], whose thickness was increased four times larger from 2.6 mm to 9.7 mm [8].…”