Study of the Piezoelectric Power Generation of ZnO Nanowire Arrays Grown by Different Methods

Abstract

The piezoelectric power generation from ZnO nanowire arrays grown on different substrates using different methods is investigated. ZnO nanowires were grown on n‐SiC and n‐Si substrates using both the high‐temperature vapor liquid solid (VLS) and the low‐temperature aqueous chemical growth (ACG) methods. A conductive atomic force microscope (AFM) is used in contact mode to deflect the ZnO nanowire arrays. No substrate effect was observed but the growth method, crystal quality, density, length, and diameter (aspect ratio) of the nanowires are found to affect the piezoelectric behavior. During the AFM scanning in contact mode without biasing voltage, the ZnO nanowire arrays grown by the VLS method produced higher and larger output voltage signal of 35 mV compared to those grown by the ACG method, which produce smaller output voltage signal of only 5 mV. The finite element (FE) method was used to investigate the output voltage for different aspect ratio of the ZnO nanowires. From the FE results it was found that the output voltage increases as the aspect ratio increases and starts to decreases above an aspect ratio of 80 for ZnO nanowires.

Comparative Study of Energy Harvesting from ZnO Nanorods Using Different Flexible Substrates

“…While the average lengths of the NRs for common paper, flexible plastic, textile fabric and aluminum foil are ~1-1.2 μm, ~2 μm, ~1.5 μm and ~2-2.4 μm, respectively, as shown in Figure 2(a-d). It is already reported that the performance of the nanogenerators was not dependent on the substrates but mainly depended on the crystal quality, effective length, diameter and density of the nanowires across the substrate (Riaz et al 2011). In our case, the aspect ratio and the density of the ZnO nanorods (NRs) have influenced the recorded output signals in consistence with other reports (Wang and Song 2006).…”

Piezoelectric Size Effects in a Zinc Oxide Micropillar

“…On the other hand, Riaz et al [20] studied the electrical potential vs. the aspect ratio of different nanowires at a fixed length of 1000 nm and varied diameters. It is found the output electrical potential increases with decreasing in diameter of the nanowires and saturated at a diameter below 12.5 nm.…”

“…Recently, various experimental studies have probed either the electrical [15,16] or mechanical [17][18][19] behavior of nanowires separately. Riaz et al [20] experimentally and initially studied electrical potential-related size effects of ZnO nanowire using both the high-temperature vaporliquid-solid (VLS) and the low-temperature aqueous chemical growth (ACG) methods. They also theoretically investigated relationship between aspect ratio and density of the nanowire and resulted electrical potential output.…”

“…In this work, by following Riaz's theoretical study [20], we have experimentally investigated piezoelectric size effects of man-made ZnO micropillars. The highoriented ZnO films are grown by pulsed laser ablation (PLD) and micropillars with different size are patterned by top-down semiconductor device processing.…”

Selective growth of tilted ZnO nanoneedles and nanowires by PLD on patterned sapphire substrates

“…caused by an externally applied pressure, thin NWs (few nm thick) offer a large surface-to-volume ratio, making them interesting for surface and bending sensitive applications. 9 Closely packed NWs with uniform spacing can improve light trapping and charge separation in nanowire-polymer solar cells. 10,11 By using tilted NWs and NNs, the field emission characteristic is controllable.…”