Question 5.7: For heterojunctions in the GaAs–AlGaAs system, the direct (Г...

For heterojunctions in the GaAs–AlGaAs system, the direct (Г) band  gap difference \Delta E^{\Gamma }_{g} is accommodated approximately \frac{2}{3} in the conduction band and \frac{1}{3} in the valence band. For an Al composition of 0.3, the AlGaAs is direct (see Fig. 3–6) with \Delta E^{\Gamma }_{g}= 1.85 eV. Sketch the band diagrams for two heterojunction cases: N^{+ }-Al_{0.3} Ga_{0.7} As on n-type GaAs, and N^{+ }-Al_{0.3} Ga_{0.7} As on  p^{+ }- GaAs^{18}

^{18}In discussing heterojunctions, it is common to use a capital N or P to designate the wide band gap material