Density of states of a two-dimensional electron gas including nonparabolicity

An expression for the density of states per unit area and unit of total energy in a two-dimensional electron gas is proposed. This density of states depends on the energy of the electrons in each subband and on the potential well function averaged in the subband by the envelope function. The resulting expression is shown to approach the density of states per unit area and unit energy, which is obtained by integrating the three-dimensional density in the potential well, in the limit of the high levels. This fact is then used for checking the validity of the expression, obtaining excellent results.