Dear Nazir,

one more ..

http://www.sciencedirect.com/science/article/pii/S0040609015005878

ZnO in thin film form is piezoelectric, provided it has a preferred c-axis orientation (002).

It can be grown easily by sputtering techniques with such preferred orientation on a variety of substrates.

There are hundreds of papers piezoelectric ZnO films and devices., and

ZnO by sputtering can be conveniently grown on unheated substrates.

K. Sreenivas

TThanks for replied.