Piezotronic Effect in Flexible Thin‐film Based Devices

Abstract

Flexible piezotronic devices based on RF-sputtered piezoelectric semiconductor thin films have been investigated for the first time. The dominating role of the piezotronic effect over the geometrical and piezoresistive effect in the as-fabricated devices has been confirmed and the modulation effect of the piezopotential on charge carrier transport under different strains is subsequently studied. Moreover, it is also demonstrated that the UV sensing capability of the as-fabricated thin film based piezotronic device can be tuned by the piezopotential, showing significantly enhanced sensitivity and improved reset time under tensile strain.

Development and progress in piezotronics

“…Additionally, it is also difficult to effectively assembly nanowires into orderly manners for further circuit integration [71,72]. Under this context, piezotronic devices based on thin films were developed [73,74]. The first practical piezotronic thin film device was developed based on RF sputtered ZnO.…”

“…This feature instantly removes two major obstacles in implementing the piezotronic effect with thin films: the difficulty in synthesizing monocrystalline thin films and its incompatibility with flexible electronics. The level of crystallinity, grain alignment and surface conductance could be further adjusted by sputtering parameters, annealing and plasma treatment and an effective thin film piezotronic device could be produced after optimizations [74,77]. TEM images of the ZnO thin film and the device's piezotronic characteristics are shown respectively in Fig.…”

In situ ZnO nanowire growth to promote the PVDF piezo phase and the ZnO–PVDF hybrid self-rectified nanogenerator as a touch sensor

“…22,23 The voltage and current output of the PZHGs are not as symmetrical as normal NGs. So it is interesting to apply the piezoelectric non-equilibrium output to recognize the touch response to pressing and releasing.…”

High‐Performance and Tailorable Pressure Sensor Based on Ultrathin Conductive Polymer Film

“…[ 10 ] However, such tasks are still challenging. [ 6,11 ] Categorized by principle, resistive, [12][13][14][15][16] capacitive, [17][18][19][20][21][22][23] piezoelectric, [24][25][26][27][28][29] piezoresistive, [30][31][32][33][34][35][36] and optical [37][38][39] pressure sensors, have been developed over the past decades. Capacitive pressure sensors based on microstructured polydimethylsiloxane (PDMS) fi lms demonstrate sensitivity up to 8.3 kPa −1 , [ 23 ] but impurities and other contaminants may cause a change of the dielectric constant and affect the sensors' performance.…”