Electrical transport properties of narrow InGaAs/InP quantum wells
Using magnetotransport measurements we have investigated the electrical properties of 3 nm wide lattice-matched InGaAs/InP quantum wells grown by metalorganic vapour phase epitaxy. We observe a significant persistent photoconductivity (PPC) effect even at room temperature. The energetic parameters of the deep level which we believe to be connected with the PPC have been determined from the variation with photon energy and from the temperature-dependent relaxation. The PPC permits the study of transport parameters as a function of the electron density. In this way, the density dependences of the in-plane effective mass and of the ratio of quantum to classical scattering times have been derived from Shubnikov - de Haas oscillations. The low-field Hall effect measurements yield peculiar anomalies in the mobility versus density curves at 77 K when evaluated on the basis of a one-band model. We show that these anomalies are caused by a second channel which can be filled with a limited number of carriers.