Effects of the Wind Speed and the Material Emplacement on the Output Signal of PZT Piezoelectric Energy Harvester

In this study the electrical signal produced from wind energy through a (Pb_{x}X_{1-x})(Zr_{y}Ti_{z}Y_{1-y-z}) piezoelectric transducer is analyzed. The material is placed onto a metal frame at different positions and voltage outputs of each are compared at different wind flow speeds and load resistance values. The absorption of the wind energy is tested by connecting a polyurethane material in parallel and perpendicular to the wind flow direction. The use of that material with optimum emplacement condition is shown to increase the voltage output by at least two orders of magnitude, where the maximum voltage output obtained is 13 V, and the maximum power is 338 μW

Effect of heat treatment on the stress and structure evolution of plasma deposited boron nitride thin films

Boron nitride (BN) thin films are deposited at 573 K by plasma enhanced chemical vapor deposition (PECVD) with ammonia (NH3) and hydrogen diluted diborane (15% B2H6 in H-2) source gases. UV-visible and Fourier transform infrared (FTIR) spectroscopies together with surface profilometry are used for the film characterization. These films are hydrogenated (BN:H) whose hydrogen content is pursued following the 1.5 h annealing process at 748 K, 923 K and 1073 K under nitrogen atmosphere. Hydrogen escape with the rising annealing temperature is observed together with increases of the compressive stress, band gap and Urbach energies. Films are composed of the hexagonal BN (h-BN) clusters that grow dominantly parallel to the substrate surface with some non-parallel planes at the edges of the clusters, which are embedded in an amorphous tissue (the so-called turbostratic structure, t-BN). Annealing seems to promote non-parallel planes, thus creating more stressful and distorted network. Most of hydrogen atoms are removed from the film annealed at 1073 K and wurtzite BN (w-BN) phase is formed with volume fraction of 57%. As a consequence or in parallel of hydrogen reduction, high compressive stress causes the cracking of the films

Influence of the nitrogen flow rate on the order and structure of PECVD boron nitride thin films

Three sets of boron nitride (BN) thin films are deposited with different N(2)/B(2)H(6) flow ratios (r = 4, 10 and 25) by plasma enhanced chemical vapor deposition (PECVD). The variations of physical properties in different deposition sets are analyzed by optical (XPS, FTIR, UV-visible spectroscopies), mechanical and electrical measurements. The films are considered to be deposited in a turbostratic phase (t-BN). Evolution of bonding configurations with increasing r is discussed. Relatively higher nitrogen flow rate in the source gas mixture results in lower deposition rates, whereas more ordered films, which tend to reach a unique virtual crystal of band gap 5.93 eV, are formed. Anisotropy in the film structure and film inhomogeneity along the PECVD electrode radial direction are investigated