# How can electrons be confined in Quantum dots?

Atoms are in the range of $1$ Angstrom while Quantum dots are in the range of $2$-$10$ nm. In any atom, $99.9$% is unoccupied. So if I have a Quantum dots of size $3$ nm and suppose in my Quantum dot, I have $20$ atoms, however when I do the math, I find that electrons can never be confined $3$ dimensionally in that quantum dot.

So how can electrons be confined in Quantum dots?

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And where is the question? –  Misha Feb 3 '13 at 6:07