Why the value of Fermi level is considered to be equal to 0.724ev?
In simple n-type AlGaAs and GaAs junction before connecting the materials, one can evaluate the Fermi levels on both sides of n-type AlGaAs and GaAs with the help of doping densities. Although the Fermi level must be flat along the junction after connection but is not clear who much Fermi level will pull down inside n-type AlGaAs and who much it will go upward in intrinsic GaAs. On the other hand, as I understand the reference of energy is considered to be at the bottom of valance band it the 1dhetero tool i.e. Ev(cap layer)=0. How the final Fermi level could be fixed at 0.724ev with the respect of bottom of valance band of cap layer (GaAs) while it is seems that it should be depend mostly on doping in highly doped AlGaAs layer?