Oxidant effect of La(NO3)3·6H2O solution on the crystalline characteristics of nanocrystalline ZrO2 films grown by atomic layer deposition

Abstract Nanocrystalline ZrO 2 films were synthesized by atomic layer deposition method using CpZr[N(CH 3 ) 2 ] 3 (Cp = C 5 H 5 ) as the metal precursor and La(NO 3 ) 3 ·6H 2 O solution as the oxygen source. La element in the deposited ZrO 2 films could not be detected as its content was below the resolution limit of the X-ray photoelectron spectroscopy. The alternative introduction of La(NO 3 ) 3 ·6H 2 O solution to conventionally used H 2 O as the oxidant effectively altered the crystalline structure, grain size, and surface roughness of the grown ZrO 2 films. Specifically, the crystalline structure of the ZrO 2 film changed from a mixture of tetragonal and monoclinic phases to monoclinic phase. The average grain size also increased, and the resulting film surface became rougher. The average grain sizes of the ZrO 2 films prepared from La(NO 3 ) 3 ·6H 2 O solution at concentrations of 10, 20, 30, and 40% were 280, 256, 208, and 200 nm, respectively, whereas that prepared using H 2 O oxidant was 142 nm. However, the concentration of La(NO 3 ) 3 ·6H 2 O solution minimally influenced the crystalline characteristics of the nanocrystalline ZrO 2 films i.e., the crystalline structure, grain size, and surface roughness except for crystallite size.