TEMPERATURE-DEPENDENCE OF THE EPITAXIAL-GROWTH OF PT ON BASAL-PLANE SAPPHIRE

We have investigated the temperature-dependent growth characteristics of epitaxial Pt(111) on Al2O3(0001) using in-situ scanning tunneling m icroscopy. For temperatures near the onset of epitaxy (600 degrees C), the Pt films grown by ion-beam sputtering, are flat and well-ordered. With increasing substrate deposition temperature, the surfaces grow r ougher and at 700 degrees C display island-on-island growth with up to 12 monosteps visible. When subjected to a post-deposition anneal of 9 50 degrees C, the Pt becomes very smooth and the initial growth temper ature becomes less important. Finally, we show that the Pt provides an excellent seed layer on which to grow and investigate metals such as Co and Cu.