and the Fermi level (EF) was estimated (see Figure ). For position 1 (only Ge layer) and position 20 (only GaInP layer), EVB-EF equal 0.4 eV and 1.2 eV, respectively. With Eg(Ge) = 0.67 eV, it means intrinsic or slightly n-type, and with Eg(GaInP) = 1.8 eV, it means an undeniable n-type. This is in contradiction to the expected p-type behavior prepared during the synthesis.