Polarization charges at spontaneously ordered (In,Ga)P/GaAs interfaces
P. Krispin1, A. Knauer2 , S. Gramlich2
Published in:
Appl. Phys. Lett., vol. 80, no. 14, pp. 2493-2495 (2002).
Abstract:
The depth-resolved electrical characteristics of n- and p-type GaAs/(In,Ga)P/GaAs heterojunctions are examined by capacitance-voltage measurements. Different epitaxial growth conditions are chosen to produce heterointerfaces with (In,Ga)P layers of various degrees of order. Irrespective of the conduction type of the heterojunction studied, we find positive [negative] sheet charges at the (In,Ga)P-on-GaAs[GaAs-on-(In,Ga)P] interfaces. The density of both interfacial charges increases with increasing degree of (In,Ga)P order. The experimental results can be completely explained by taking into account the spontaneous polarization of ordered (In,Ga)P. The polarization difference between ordered (In,Ga)P and GaAs (no polarization) results in opposite sheet charges at the two complementary interfaces with GaAs, in accordance with theoretical predictions.
1 Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany
2 Ferdinand-Braun-Institut für Höchstfrequenztechnik, Albert-Einstein-Straße 11, D-12489 Berlin, Germany
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