Over the past ten years dozens of proposals for large-scale quantum computers have been developed, none of which are very close to realization. The significant impediments to semiconductor implementations in particular are discussed in an introductory article that we recently published in the MRS Bulletin (link, pdf). This article highlighted the need for the development of atomic-scale fabrication techniques that could ultimately enable the high level of device perfection necessary for scaleable quantum computers. These ideas have been the primary motivation for our work on hydrogen terminated silicon surface devices.
