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The Electronic System







                                                                                    ξ
                                                                 C



                                                          2
                                                      2ξ C –  ξ 2
                                                      -----------------------------
                                                            2
                                                        2
                                      – tan ξ          C –  2ξ

                Figure 3.4. Graphical solution for equation (3.33). The intersection of the two expres-
                                          ⁄
                                        2
                                                  2
                                             2
                sions  tan–  ξ   and  2ξ C –(  2  ξ ) ( C –  2ξ )  , indicated by the circle, is the first solution
                point. Also see Figure 3.4.

                                                   E





                Figure 3.5. Change in energy E
                                     a
                as a function of well width  , for
                the first solution of equation
                (3.33), as given by the graphical
                solution (marked with a circle) in                                  a
                Figure 3.4.




                             have to be succeeded by numerics. Since semiconductor structures are
                             becoming more and more complicated, there is no way of dealing with
                             the electronic structure calculations in an analytical way. The reader may
                             now ask why all this rather theoretical material is discussed in detail


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