“…Piezoelectric ZnO found applications in surface and bulk acoustic wave devices (Gorla et al, 1999). it is also a semiconductor with a wide band gap of 3.37 eV at room temperature, has a large exciton energy of 60 meV, and thus could be used as a functional material in optics and optoelectronics (Ohta and Wosono, 2004;Waag et al, 2002). Transparent and conductive ZnO films are finding applications as electrodes in solar cells.…”