Quantum confinement
= Quantum confinement
<Quantum confinement> restricts a particle's wavefunction over a length comparable with its characteristic quantum length scales, altering the allowed <energy levels> relative to a bulk material. For a parabolic band confined over width $L$, a characteristic spacing is of order $\hbar^2/(m^*L^2)$, with boundary-dependent numerical factors. A <quantum dot> confines all three directions; confinement in only one direction can leave continuous motion in the other two. Finite barrier height and interactions modify the simplest infinite-wall estimates.