Atomic scale electronics using isoelectronic centers

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Quantum dots (QDs) have revolutionized the amount of control we have over the energy and behavior of charged carriers in semiconductor materials. However, as a result of the large number of atoms composing them (from 1000 to 100,000), it is nearly impossible to fabricate two identical QDs or even a single one with exactly the desired characteristics. Unfortunately, this critical issue has been impeding the realization of some of the most exciting proposals involving QDs, from more efficient lasers to powerful quantum computers. As an alternative to QDs composed of tens of thousands of atoms, we propose using Isoelectronic Centers (ICs) composed of one, two, or any small number of isoelectronic traps to implement novel electronic functionalities at an atomic scale in semiconductor materials. The originality of this program stems from the fact that ICs combine in one system many important advantages that were only available in either crystalline defects like one-atom impurities or QDs: ICs can be made from a large selection of impurities and host materials, their emission energy and other characteristics are broadly tunable, they exhibit low inhomogeneous broadening and they have perfectly defined symmetries. In this research program, we propose to 1) develop a firm understanding of the physics governing the behavior of this little-studied nanostructure and 2) exploit its unique characteristics for a number of applications such as, for example, the generation of entangled photons and the realization of a single spin memory with enhanced coherence time. Research on ICs has the potential to open up opportunities in many areas where conventional quantum dots and other nanostructures were previously envisioned. Even more significantly, ICs can form the necessary building blocks for the development of atomic-sized electronics, a topic destined to become a prominent and very active research field in a near future. Finally, the knowledge and experience acquired by graduate students are of strategic importance for companies with activities involving spectroscopy, semiconductor materials, optical devices and other precision instrumentations.