Deep level studies of Hg1−xCdx Te. I: Narrow-band-gap space-charge spectroscopy

Trapping effects in p-type Hg1−xCdx Te (0.2<x<0.4) have been surveyed using three techniques. These were deep level transient spectroscopy (DLTS), admittance spectroscopy (AS), and thermally stimulated current (TSC). All three techniques were able to identify deep traps in Hg1−xCdx Te even for band gaps less than 0.1 eV. DLTS is best able to characterize deep traps, admittance spectroscopy is able to quickly survey majority-carrier traps, and TSC is limited in Hg1−xCdx Te by leakage currents. Deep traps were seen in all of the samples studies in concentrations of 1014–1016 cm−3. Double pulse DLTS techniques have been used to identify the electron capture cross sections for specific hole traps. This allows the complete characterization of recombination centers. A donor-like Shockley-Read generation-recombination center occurring near midgap may be common to p-type Hg1−xCdx Te, where the doping is due to mercury vacancies.