Growth kinetics of a perfectly flat Bi(110) film during low-temperature deposition and subsequent annealing

Abstract

We investigated the kinetics of the formation of a perfectly flat four-monolayer (ML)-high Bi(110) film on the Si(111)√3 ×√3-B substrate by the deposition of 4.8 MLs of Bi atoms at 90 K and subsequent annealing to room temperature. Scanning tunneling microscopy showed that round, amorphous Bi islands nucleated on a two-ML-high Bi layer at 90 K. Surface X-ray diffraction revealed that approximately 50% of the two-ML-high Bi layer already had the black phosphorus (BP)-like Bi(110) crystal structure just after deposition. The coverage of the BP-structure two ML-high Bi(110) layer started to increase at 200 K and reached unity at 220 K during annealing. The second BP-structure Bi(110) bilayer appeared at 200 K and was complete at 300 K. Monte Carlo simulations indicated that Bi atoms were readily released from the amorphous islands and attached to the edge of the lower layer, increasing its area. The amorphous islands with an area above a critical size transferred to the Bi(110) terrace, increasing the coverage of the second Bi(110) bilayer.