Stable Chiral Si Surface: Si(17 15 3)3 × 1

Abstract

It is known that when Si(551) substrates are heated in an ultrahigh vacuum, Si(551) substrate is faceted to form a ridge-and-valley nanotexture. In this study, the facet plane was determined to be (17 15 3) by means of the precise analysis of the reflection high energy electron diffraction (RHEED) and the scanning tunneling microscopy (STM). RHEED results concluded that 3 × 1 super structure was formed on the Si(17 15 3) as a stable structure. STM images showed that parallel grooves were running parallel to [015] direction. The spacing between the grooves was random after flashing at 1250°C, but converged into the 3 × 1 periodicity after annealing at 700°C. The (17 15 3) surface must be crystallographically homo chiral. In the STM image of the 3 × 1 structure, three protrusions were arranged between the grooves. The present results inferred that the ridge-and valley structure of Si(551) consists of the chiral (17 15 3)3 × 1 and its enantiomorph (15 17 3)3 × 1. Such alternative chiral nano-texture is a promising substrate for the formation of novel chiral materials.