Atomically Precise Manipulation of Silicon Properties: Material Modifications That Enhance Performance and Manufacture of Energy Conversion and Microelectronic Devices

Existing optical and electronic devices, although in some cases scaled down to remarkable levels (few nanometer dimensions in state-of-the-art integrated circuits), are not considered to be truly atomically precise in nature. The goal of this Phase I project is to employ atomic precision in a type of material deposition process known as molecular beam epitaxy in order to produce a new generation of high-performance devices. Atomically precise crystal growth will be used to produce a new generation of ultra-thin single- crystal semiconductor-metal quantum heterostructures. These atomically precise heterostructures will enable new levels of performance in optoelectronic devices such as high sensitivity photodetectors, high gain and radiation hard electronic devices such as heterojunction bipolar transistors, and superconducting quantum interference devices that are used in advanced quantum computers. These quantum heterostructures and devices will be enabled by a combination of ultra-clean ultra-high vacuum crystal growth (known as epitaxy) in conjunction with precisely-dosed atomic hydrogen to facilitate atomically abrupt single-crystal interfaces that are free of defects. In Phase I of this project, ultra-thin single-crystal layers of the semiconductor silicon (Si) and the metal aluminum (Al) will be carefully deposited with lattice matching (the same atomic spacing) onto commercially available transparent, insulating yttria-stabilized zirconia (YSZ) single-crystal substrates. Crystal deposition temperatures and source material fluxes will be controlled so that interfaces are abrupt and unwanted alloy formation is avoided. The physical, electrical, and optical characteristics of these quantum heterostructures and prototype devices will be carefully measured and analyzed and benchmarked against existing material systems. Commercial applications include civilian and military markets where high performance atomically precise opto-electronic devices are needed.