Photoluminescence study of the 2D electron gas formed at the interface of strained InGaAs/InP single heterostructures

Photoluminescence measurements have been performed in two series of strained InxGa1-xAs/InP single heterostructures, grown by molecular beam epitaxy with different epilayer thicknesses. Tensile strained samples (xIn = 0.508) and compressive strained samples (xIn = 0.543) have been investigated. An emission 30 meV below the excitonic recombination has been observed in these structures and we ascribe it to a recombination between photocreated holes and electrons from the two-dimensional electron gas formed at the InGaAs/InP interface. The role of the epilayer thickness on the photoluminescence recombination mechanism of the two-dimensional electron gas is discussed. Measurements of the photoluminescence temperature dependence have revealed the heavy-hole and light-hole splitting in this emission. The value of this splitting is in very good agreement with the expected values obtained by double crystal X-ray diffraction measurements