Combined HRTEM and High Spatial Resolution Analysis of Homologous Compounds InMO3(ZNO)m By A 300kv FE-TEM

Abstract

A series of homologous compounds InMO3(ZnO)m (M=In, Fe, Ga and Al, m=integer) has been synthesized successfully by the present authors. From x-ray diffraction, the strutcure is considered to be a layered structure, consisting of InO2−1-(In-O layer) interleaved with M/ZnmOm−l1+ (M/Zn-O layer). The space group is assigned to be R3m when m is an odd number, while it is P63/mmc when m is an even number. The distribution of M atoms within the M/Zn-O layers is considered to be random. However, from electron microscopy study, the existence of the modulated structures showing non-integral periodicities has been observed. The high spatial resolution EDS analysis using 0.5 nm electron probe diameter under a 300kV FE-TEM showed that the sinusoidal modulated structure is caused by the ordering of M atoms within the M/Zn-O layers. In the present study, modulated structures of InMO3(ZnO)13, where M atoms consists of two metals such as In and Fe, Ga, Al and Fe are studied by combined use of HRTEM and high spatial resolution EDS analysis using a 300kV FE-TEM.