A simple and inexpensive circuit for emission and capture deep level transient spectroscopy

A simple and inexpensive circuit for deep level transient spectroscopy is described, which allows rapid characterization of emission as well as capture activation energies of deep levels. This flexibility of making capture activation studies affords more information on defect morphology than the more standard emission activation studies. This is demonstrated by making a representative capture activation energy measurement on the EL6 level in undoped n-type GaAs of 0.484±0.005 eV. Also the spectrometer has shown better performance than earlier reported systems by its ability to resolve the side peaks of the EL6 level, for which emission activation energies of 0.29 and 0.4 eV are assigned. Constructed around a commercially available capacitance meter and pulse generator, the control circuitry is designed and developed using inexpensive and off-the-shelf integrated circuits.