GROWTH MODE ISSUES IN EPITAXY OF COMPLEX OXIDE THIN-FILMS

We discuss the hetero-epitaxy of complex oxides taking YBa2Cu3O7-delta as an example. Special emphasis is on films grown by pulsed laser dep osition (PLD), but other growth techniques are also discussed. Lattice mismatch in three directions is responsible for the fact that a real single crystalline YBa2Cu3O7-delta thin film has not yet been obtained . Nevertheless, growth features typically observed on single crystals (e.g. growth spirals as well as repeated nucleation and growth) are of ten found on YBa2Cu3O7-delta thin films. We discuss how surface diffus ion and supersaturation influence the surface morphology (as observed by atomic force and scanning tunnelling microcopies (AFM/STM)) of comp lex oxide thin films. In particular, we conclude that the kinetic ener gy of the impinging adatoms affects the surface diffusivity and theref ore the growth mode. (C) 1998 Chapman & Hall.