This article describes a technique to detect shallow levels in highly compensated ZnSe by photoinduced admittance spectroscopy (PIAS). Nitrogen doped ZnSe with a Schottky barrier on top has been investigated, and the photovoltage measurements show that the electric charge in the depletion layer becomes positive under high intensity illumination with photon energies larger than the energy gap of ZnSe. An electron trap with an activation energy of 50 meV was obtained from the PIAS measurement. The accuracy of this technique is confirmed by reconstruction of the temperature dependence of the capacitance and conductance by a computer simulation. ©1997 American Institute of Physics.