液相外延生长Pb(Zn1/3Nb2/3)O3-PbTiO3膜及生长机理研究

采用PbO作助溶剂,我们在钛酸锶(STO)衬底上用液相外延方法生长了一层具有特定取向的PZNT岛状外延膜,并通过引入c轴取向的PZT过渡层后,使原来的岛状三维生长转变为二维生长,显著改善了外延膜的质量,获得了几个微米厚、较完整的PZNT膜.实验证明:在氧化镁和铝酸镧(001)基片以及STO(110)/(111)衬底上,PZNT晶粒以自发形核为主,外延生长膜主要呈现岛状形貌;取STO(001)衬底,膜颗粒取向一致性好,并可获得完整的PZNT膜.

LPE Growth and Growth Mechanism of Pb(Zn1/3Nb2/3)O3-PbTiO3 Films

An island-shaped PZNT film on the STO substrate with an orientation relation of (001)_(PZNT)// (001)_(STO) was grown by the liquid phase epitaxy method using PbO as flux.When a highly c-axis oriented PZT film is introduced as the seed,the quality of PZNT film has been improved remarkably and an approximately complete PZNT film with a thickness of several microns can be achieved.Moreover,the PZT seed layer makes the PZNT growth transform markedly from a three-dimensional mode into a two-dimensional mode.On the basis of the experimental results,three kinds of possible growth modes have been suggested. The spontaneous nucleation is predominant when PZNT grains grow on the(001) plane of MgO or LaAlO_3 substrates,and(110)/(111) planes of the STO substrate as well.The heterogeneous epitaxy growth is in the majority when the STO(001) substrate is applied.A nearly homogeneous epitaxy growth with the achievement of a complete PZNT film arises eventually when the PZT/STO is used as a seed film.