The quest for the quantum dot

Semiconductor devices that confine electrons within two-dimensional quantum wells are already in production. The zero-dimensional quantum dot promises super-efficient lasers with the last word in spectral purity. The author briefly discusses the definition of the electron and then goes on to discuss in more detail the quantum well obtained in the case of a GaAlAs-GaAs heterojunction. Further quantisation of the electron energy produces one dimensional quantum wires. By removing the one degree of freedom of the quantum wire leaves the quantum dot, zero degrees of freedom, the ultimate in energy quantisation