Deep levels inn-type high-purity (HP) detector grade germanium are studied using optical deep level transient spectroscopy (ODLTS). In this technique, optical injection (using light of above band gap energy) from the back ohmic contact together with a suitable sample configuration results in the detection of centers in the minority half of the band gap. Six deep minority carrier traps are detected in typicaln-type HP germanium which turn out to be the same defects as found earlier in typicalp-type HP germanium as majority carrier traps. These deep defects are mainly copper related. A formula is deduced to calculate concentrations from the ODLTS spectra. It is shown that inn- andp-type HP germanium not only the same defects are present but that their concentrations are also comparable. ©1997 American Institute of Physics.