Formation of anomalously wide Si(1 1 1)3×3 clean surface and its stability

High-temperature scanning tunneling microscope observation has been performed to investigate formation of a Si(1 1 1)3×3 structure and its stability on a quenched surface. Formation of anomalously wide Si(1 1 1)3×3 domains was observed by increasing adatom density of Si on quenched surface below the transition temperature between disordered “1×1” and ordered simple adatom structures. By adding Si adatoms most of the simple adatom structure transformed into the 3×3 structure. Domain boundaries between adjacent 3×3 domains are straight and along the 〈1 1 0〉 direction. The 3×3 structure transforms into the 2×n structure by annealing and Si cluster increases in number to maintain Si adatom density on the surface. This indicates that the 2×n structure is energetically more stable than the 3×3 structure.