Characteristics of piezoelectric ZnO/AlN−stacked flexible nanogenerators for energy harvesting applications

Abstract

Flexible piezoelectric zinc oxide (ZnO)-based nanogenerators (NGs) using an aluminum nitride (AlN) interlayer are proposed for high-efficiency energy harvesting applications. The effects of the AlN interlayer on device performance are studied. Use of the AlN interlayer in ZnO-based vertically integrated NGs (VINGs) results in a significant improvement in terms of the magnitude of the output voltages of up to 200 times when compared with a ZnO-based VING without any AlN interlayer. The improved device energy conversion efficiency is mainly attributed to a high contact potential barrier that the AlN interlayer provides in VINGs, along with the relatively high dielectric constant and large Young's modulus of the AlN material. In addition, the effects of AlN thickness on the electric potential and device performance of the VINGs are investigated through observation of the output voltages of ZnO-based VINGs with thickness/position-controlled AlN interlayers. Our findings in this work are expected to provide effective and useful approaches for realizing highly energy-efficient ZnO-based NGs and their extended applications, including self-power sources and sensor devices.

Recent Progress of Janus 2D Transition Metal Chalcogenides: From Theory to Experiments

“…The piezoelectric effect is a linear electromechanical interaction in insulating crystalline materials without inversion symmetry . Piezoelectric materials have extensive applications in the electronic, energy, and medical fields, such as sensors, actuators self‐power sources, and low‐power logic switches . In‐plane piezoelectricity has been obtained in a series of 2D materials, including h‐BN, MX 2 , and NX monolayers .…”

Formation and Characterization of Various ZnO/SiO2-Stacked Layers for Flexible Micro-Energy Harvesting Devices

“…Some research teams have used insulators or other semiconductor materials to form a good potential barrier to increase output voltages [19]. Other research using AlN or various oxides (MoO x , Cu 2 O, and NiO) has been reported [14,16,18,20]. Despite such intensive research, only few studies were published using SiO 2 as an insulator [21].…”

“…Their fabrication seems to be cost-effective because all that is required to fabricate these micro-energy generators is simply the stacking of thin film layers. Similarly, high-efficiency piezoelectric ZnO-based nanogenerators have also been developed for energy harvesting applications by forming ZnO/AlN-stacked layers [14] and adopting free-carrier-modulated ZnO:N piezoelectric thin films [15]. Moreover, there have been attempts to improve the piezoelectric materials or the device performance by adopting new electrodes or forming a p-n junction to block the screening effect based on energy band considerations [15][16][17][18].…”

Single-pot ZnO nanostructure synthesis by chemical bath deposition and their applications

“…ZnO is one of the most favorable materials widely used in electronics (transistors) [4,5], sensors [6][7][8], catalysts [9][10][11], light emitting devices [12][13][14][15], piezoelectric devices [16][17][18][19][20], solar cells [21][22][23], sunscreens [24,25], lasers diodes [26,27], hydrophobic surfaces [28,29], magnetic data storage [30,31], water disinfection [32], antiviral agent [33,34], anti-cancer agent [35], hazardous waste remediation [36], flexible plastic devices [37], degradation of pollutants [38], energy conversion and storage devices [22,[39][40][41]. ZnO is a wide band gap semiconductor (3.3 eV) with a high excitation binding energy of 60meV [42] at room temperature.…”