A MODULATED STRUCTURE OF IN2O3(ZNO)(M) AS REVEALED BY HIGH-RESOLUTIONELECTRON-MICROSCOPY

A modulated structure appearing in the homologous series of compounds In2O3(ZnO)(m) (m = 3, 6, 10, 13, 15, 17 and 20) has been studied by hi gh-resolution transmission electron microscopy. The basic structure of these compounds consists of InO21- layers interleaved with InZnmOm+11 + layers along the c axis. The space groups are either hexagonal P6(3) /mmc for m = even numbers or rhombohedral R(3) over barm$ for odd numb ers. The modulated structure showing a zig-zag shape has been found fo r m > 6. It is shown that the non-integral periodicities for the modul ation waves increase with higher values of m numbers. The modulated st ructure model where trivalent In atoms are ordered within In/Zn-O laye rs is proposed.