TIME-RESOLVED HIGH-RESOLUTION ELECTRON-MICROSCOPY OF STEP-DIFFUSION OF TUNGSTEN ATOMS ON MGO(001) SURFACES

The surface diffusion process of tungsten(W)-atoms along (100) steps o n Mg0(001) surfaces was studied by high-resolution electron microscopy (HREM) in the time resolution of 1/60 s. The W-atoms were prepared on single crystalline Mg0(001) films at 300 degrees C by the vacuum depo sition of WO3 or W-metal in a UHV transfer chamber. Analysis of the re corded images revealed the individual jump-process of the W-atoms alon g the steps at a substrate temperature from room temperature to 400 de grees C. The diffusion process on terraces and along steps was compare d from the viewpoints of the jump distance, dwelling time and local di ffusion constant. (C) 1997 Elsevier Science B.V.