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 , a characteristic spacing is of order , 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.
Electronic confinement in two transverse directions leaves propagating motion along the wire. Each open transverse subband supplies longitudinal transport channels, with spin counted explicitly. A wire may be ballistic or disordered; one-dimensional subband structure alone does not ensure perfect transmission.
Carrier confinement quantizes electronic and hole states and changes transition energies, joint density of states and envelope overlaps. A waveguide or cavity confines electromagnetic modes and changes optical overlap, resonances or emission rates. Both can occur in a semiconductor light source, but a small electronic island is not automatically a designed optical cavity.
Articles by others on the same topic
There are currently no matching articles.