  Epitaxial growth of atomically-sharp interfaces serves as one of the main
building blocks of nanofabrication. Such interfaces are crucial for the
operation of various devices including transistors, photo-voltaic cells, and
memory components. In order to avoid charge traps that may hamper the operation
of such devices, it is critical for the layers to be atomically-sharp.
Fabrication of atomically sharp interfaces normally requires ultra-high vacuum
techniques and high substrate temperatures. We present here a new self-limiting
wet chemical process for deposition of epitaxial layers from alkoxide
precursors. This method is fast, cheap, and yields perfect interfaces as we
validate by various analysis techniques. It allows the design of
heterostructures with half-unit cell resolution. We demonstrate our method by
designing hole-type oxide interfaces SrTiO3/BaO/LaAlO3. We show that transport
through this interface exhibits properties of mixed electron-hole contributions
with hole mobility exceeding that of electrons. Our method and results are an
important step forward towards a controllable design of a p-type oxide
interface.
