Hall mobility and carrier concentration measurements are done on In0.53Ga0.47As layers grown by liquid phase epitaxy from melts containing 0.1–0.18 wt % Er. The carrier concentration in the layer decreased to 2×1014 cm-3 upon the addition of 0.16 wt % Er to the growth melt but the corresponding mobility of the layer increased only marginally. A detailed analysis of the temperature-dependent Hall mobility data for the samples using a theoretical curve fitting technique revealed that the donor impurities in the material are reduced to a greater extent compared to the acceptors, making the layers compensated. The experimental mobilities are further compared with the published values of theoretically calculated mobilities for InGaAs with similar compensations. It is shown that the space charge scattering effects are to be considered in order to get a good agreement between the experimental and the theoretical values. © 2000 American Institute of Physics.