INFLUENCE OF ARSENIC ADSORPTION LAYERS ON HETEROINTERFACES IN GAINAS/INP QUANTUM-WELL STRUCTURES

The 5 K photoluminescence of GaInAs/InP QWs a few monolayers in thickness has been used as a probe for investigating the influence of AsH3 concentration and growth temperature on the formation of additional interface layers between the GaInAs of the QW and the InP barrier. Increasing AsH3 concentrations and decreasing growth temperatures shift the QW peak energies to longer wavelengths, i.e., they increase the effective thickness of the QWs. The effect is discussed in terms of different growth regimes in MOVPE with different arsenic coverages of the GaInAs surface in analogy to (001) GaAs with (2 X 4) -like or c (4 X 4) -like arsenic-terminated surfaces. In the latter case the excess As is an effective source for As carry-over into the upper InP barrier of the QW resulting in the formation of graded InAsxP1-x interface layers.