DLTS combined with perturbed angular correlation (PAC) on radioactive In-111 atoms in Ge

We combined two different techniques to study deep level defects in germanium on a microscopic scale: Deep Level Transient Spectroscopy (DLTS) and Perturbed Angular Correlation (PAC). The combining element is the use of radioactive probe atoms on which both techniques are focused. For this purpose radioactive In-111 atoms are implanted in Ge subsequently prepared as Schottky contact. During the decay to Cd-111 DLTS is measured repeatedly. A level at E(V)+0.15 eV increasing in concentration according to the lifetime of In-111 can be assigned to the daughter atom Cd-111. In a further series of experiments, additional electron irradiation is performed on the In-111-doped samples and the DLTS again is measured repeatedly. A new level at E(V)+0.33 eV is detected, which decreases with the In-111 lifetime. In the course of the DLTS measurements PAC was measured on the same samples. From those spectra the trapping of a defect at the In-111 probes characterized by a quadrupole interaction frequency 52 MHz can be deduced. Since this is the only defect component seen in the PAC spectra (except for the substitutional component), we identify this component with the defect seen by DLTS. (Author)