Quantum Dot Charge and Spin Memory Devices

This chapter deals with the quantum dot charge and spin memory devices. The determination of coherence and inhomogeneous spin dephasing times for single electrons and holes in self-assembled QD nanostructures are one of the major challenges. These quantities may be accessible using time-resolved coherent optical measurements or by combining the spin storage experiments with electron spin resonance techniques. Another important aspect is the efficient readout of single electron spins. This may be achieved optically by incorporating the dots within microcavities with enhanced collection efficiency and, thus, enhanced sensitivity. High-efficiency electrical readout of such optically prepared spin systems may also be feasible. The use of the spin degree of freedom in quantum dots for more complex quantum operations will also require extension of the present techniques to coupled dots or arrays of dots.