Fabrication of Schottky barrier diodes based on ZnO for flexible electronics

The manufacturing of electronic devices over flexible substrates becomes a very interesting approach for novel applications. However, the possibility to implement the full technological fabrication procedure is limited for the thermal properties of the flexible substrates. In this paper, the synthesis of zinc oxide nanoparticles by solvothermal process at three different temperatures is presented. Nanopowders synthetized at different temperatures by the solvothermal process were characterized by X-ray diffraction, UV–Vis spectroscopy, and scanning electron microscopy, SEM. Characterization results show that, ZnO powders present a hexagonal wurtzite structure, a band gap magnitude around 3.28 eV, and the particle size is reduced as the temperature is increased. Additionally, fabrication of Schottky barrier diodes based on zinc oxide nanoparticles over polyethylene terephthalate (PET) substrates is shown. The maximum temperature used in the diode fabrication was 150 °C, which is compatible with flexible substrates. Electrical characterization of fabricated diodes showed the thermionic emission as the main conduction mechanism. The full diode parameters were extracted from reverse and forward current–voltage characteristic. The extracted parameters were barrier height ~ 0.54 eV, series resistance of 660 Ω, and an ideality factor of 5.6.