Part 2 : Nanostuctures Module 2 : Electrons in lower dimensions
Lecture 1 : Quantization in Heterojunction system
 
Quantum Well

Fig 2.2 : Schematic Quantum well structure for heterojunction

In the simplest energy band picture for a quantum well made of AlGaAs-GaAs-Al-Ga-As structures, the band gap difference is distributed between the valence and conduction band in such a way that both electrons and holes are confined to the smaller band gap GaAs layer. Such a heterojunction is called Type I system. At 300 K, the band gap of AlxGa1-xAs is found empirically as (at point in
k-space)

where x is the Al mole-fraction.