A method for the determination of interface properties between a depleted heteroepitaxial layer and a substrate is presented. The method is based on the measurement of the zero bias capacitance of a metal gate that forms a Schottky contact with the depleted epilayer. The interface charge density can be extracted regardless of the exact values of the energy band discontinuities. A microscopic electrostatic analysis of the interface is presented which takes into account the effects of interface charges and interface dipoles. Experimental results are presented for the case of ZnTe epilayers grown by metal organic chemical vapor deposition on CdTe substrates. ©1995 American Institute of Physics.