The strong interest in low-dimensional semiconductor structures originates from their exciting electronic properties, which can have an important impact on the performance of electronic and photonic devices. Quantum dots (QDs), also known as quantum boxes, are nanometer-scale islands in which electrons and holes are confined in 3D potential boxes. QDs are expected to show a 0D, δ-function density of states (DOS) and are able to quantize an electron's free motion by trapping it in a quasi-0D potential confinement. As a result of the strong confinement imposed in all three spatial dimensions, QDs are similar to atoms and are, in fact, frequently referred to as "artificial atoms." Due to this confinement, novel physical properties will emerge that can lead to new semiconductor devices as well as drastically improved device performance.
As the particles are confined in all three dimensions, there is no dispersion curve, and the DOS is dependent only on the number of confined levels. For a single dot, only two (spin-degenerate) states exit at each energy level, and the plot of the DOS versus energy will be a series of δ functions.
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