Explanation

If a thin layer of different semiconductor interlayer is grown between the same two thicker semiconductors, as long as the conduction band edge of the interlayer materials is lower than the conduction band edge of the two edge layers, or the valence band edge of the interlayer is higher than the valence band edge of the two edge layers, a three-layer structure with two edge layers as potential barriers and the interlayer as potential wells is called a quantum well. If the thickness of the potential well layer is small enough to be comparable to the electron de Broglie wavelength, the energy of the electrons or holes in the well moving in the direction perpendicular to the junction plane is quantized into a series of discrete values determined by the well width, well depth and effective mass of particles. This materials is called a single quantum well materials. The materials obtained by periodically repeating the single quantum well structure is called multi quantum well materials if the thickness of the barrier layer is large enough that the electronic wave functions in two adjacent potential wells cannot be coupled with each other.

Classification