The zigzag-shaped potontial in crystals with “nipi-Superstructure” (a periodic array of n- and p-doped layers, separated from each other by zones of the intrinsic material) splits the bands into subbands. As a consequence the electronic properties as a function of photon frequency or of external fields should show oscillations reflecting the subband structure. Furthermore these crystals should show interesting features, which are based on the weak interaction between carriers of different impurity layers, and on the change of the amplitude of the superstructure potential with the degree of excitation. Thus, the absorption coefficient, as well as the recombination radiation shows a strong red shift, which depends on the degree of excitation. The efficiency for light storage is high. The application of external fields has drastic effects on the absorption coefficient and on the intensity and frequency of luminescence. At high fields electroluminescence with high efficeincy eventually may be observed.
Das zickzack-formige Potential in Kristallen mit „nipi-Uberstruktur” (einer periodischen Anordnung von n- und p-dotierten Schichten, mit Zonen des reinen Materials dazwischen) fuhrt zu einer Aufspaltung der einzelnen Bander in „Unterbander”. Diese Aufspaltung sollte zu einer oszillatorischen Abhangigkeit der elektronischen Eigenschaften von auseren Feldern oder Photonenenergien fuhren. Daruber hinaus sollten solche Kristalle neue Eigenschaften zeigen, die von der schwachen Wechselwirkung zwischen Ladungstragern in verschiedenen Schichten und der Abhangigkeit des Uberstrukturpotentials vom Anregungsgrad herruhren. Absorption und Lumineszenz zeigen eine starke, vom Anregungsgrad abhangige Rotverschibung. Das Lichtspeicherungsvermogen ist hoch. Durch asere Felder konnen der Absorptionsindex sowie die Intensitat und das Spektrum der Lumineszenz drastisch beeinflust werden. Unter geeigneten Bedingungen sollte auch Elektrolumineszenz mit hoher Ausbeute moglich sein.
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