Isoelectronic quantum dots

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Quantum structures like quantum wells, wires, and dots have revolutionized the amount of control we have over electronic properties of materials by allowing us to manipulate the electric charge wavefunctions far beyond what is possible in bulk systems. Faced with a limit to the integration of conventional electronics, these structures, composed of thousands to millions of atoms have opened up exceptional opportunities for the creation of the next generation of devices. The research proposed here focuses on Isoelectronic Quantum Dots (IQD) composed of a few isovalent impurities and, anticipating long-term needs for ever larger integration, aims at developing new approaches for the creation of atomic-size devices. The objectives of this program are: To advance the understanding of the physics governing the behavior of atomic-scale quantum dots and to explore their advantages with respect to larger quantum structures. To achieve the first objective, we will use high-resolution single dot spectroscopy to survey the electronic and excitonic states of IQDs as a function of the nature of the isoelectronic impurity, the number of atoms composing the dot, and their configuration and symmetry. After having established a firm understanding of their properties, we will use IQDs to demonstrate several promising applications. For example, we propose using the unique characteristics of the binding of an electron to an IQD to achieve a gate-controlled single-spin memory: This memory can be written through the technique of optical orientation, storage is achieve with a segregating electric field, and finally, the memory is read from the polarization of the emitted photon. IQDs have been very little studied and offer great potential for significant findings. Aside from the fundamental knowledge gained, this research should open up new opportunities for the development of atomic electronics, a topic destined to become a prominent and very active research field in the near future.