Study of low temperature solution-processed amorphous KNN thin films using PFM

Extraction of Electromechanical Coefficients from Capacitance–Voltage Measurements of Unannealed Solution‐Processed KNN Thin Films: Effects of Frequency and Electrostatic and Mechanical Deformation

“…[ 35,36 ] However, at higher applied voltage levels, the relationship can potentially depart from strict linearity due to electrostatic and mechanical deformation effects. To contrast the present work from earlier PFM measurements, [ 37 ] we note that we have previously distinguished nonlinear effects arising from a nonlinear response of the composite film‐tip system at high biases and identified PFM measurements with the first harmonic amplitude of displacement () rather than d 33 per se as the tip's electrostatic interaction with the sample plays a strong enough role to make PFM a difficult method for d 33 measurement. [ 16,38 ]…”

“…To contrast the present work from earlier PFM measurements, [37] we note that we have previously distinguished nonlinear effects arising from a nonlinear response of the composite film-tip system at high biases and identified PFM measurements with the first harmonic amplitude of displacement (FHA d ≡ Tip displacement…”

“…KNN-based thin film and other material related characterizations can be found in our previous work. [37] For metal-piezo-metal (MπM) capacitor, as shown in Figure 4, two sets of prefabricated shadow masks with three different radii (R 0 ) circular holes were used to thermally deposit 50 nm silver (Ag) (Angstrom Engineering) on top of the spin-coated KNN thin film (h 0 ¼ 70 nm), resulting in six different area devices (1 to 15 mm 2 ) with the same thickness (Figure 1a). The fabricated device structure is shown as the schematic in Figure 4, where KNN is sandwiched between Ag (top contact) and Cr/Au-deposited SiO 2 substrate (bottom contact).…”

“…Calculated d 33 using the derived equation (Equation ( 9)) compared with the d 33 from literature using different techniques: BC ¼ BerlinCourt, PFM ¼ piezoresponse force microscopy, LDV ¼ laser Doppler vibrometry, and CV ¼ capacitance-voltage for estimation of electromechanical coefficient (d 33 ). The comparison contains our previous work on the estimation of FHA d using PFM on KNN thin films [37] and present work, corresponding to thermally unannealed samples, while most other studies are for annealed samples. Owing to the use of inverse piezoelectric effect to determine d 33 in our work, our measurements may be an underestimate by as much as 10-15%.…”

Flexible Tactile Sensors Using AlN and MOSFETs Based Ultra-Thin Chips

“…In this regard, their inorganic counterparts such as aluminium nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), potassium sodium niobate (KNN) etc. offer better solution [25][26][27][28]. Amongst these, PZT is not recommended due to presence of toxic lead element (over 60 wt.%) [29].…”