Stability of Sputter Deposited ZnO:Cr Films Against Acids

Abstract

ZnO:Cr films were deposited on water-cooled soda-lime glass substrates at room temperature in an Ar atmosphere by rf magnetron sputtering of a ZnO target on which Cr chips were placed. The films exhibited extraordinary stability against acids such as HCl or HNO 3 , and also high resistivities similar to those of ZnO films. The addition of Cr suppressed the growth of ZnO grains which resulted in the formation of a dense film with a smooth surface. The stability ahd high resistivity displayed by the ZnO:Cr films can be attributed to the formation of a chromium-oxide-rich grain boundary.