The energy spectrum and some properties of lead sulphide implanted with oxygen

Condensed matter physics

Spectral dependencies of optical reflection and absorption coefficients in lead sulfide implanted with oxygen ions and annealed in vacuum have been investigated at T = 300 K. It was found that the average value of hole concentration within the sample space area where properties were modified by ion implantation and vacuum annealing was equal to (3.25 ± 0.30)•1018 cm–3. The depth of the space in question was estimated and its quantity was shown to make the tenths of micrometers. It was demonstrated that because of annealing process oxygen ions occupied places in the chalcogen sublattice healing anion vacancies. It was also found that vacuum annealing of lead sulfide with implanted oxygen did not cause elimination of all anion vacancies. Moreover, the concentration of sulfur vacancies increased considerably in comparison with its value in the initial samples non-subjected to ion implantation. This fact testifies that oxygen in lead sulfide possesses acceptor action which is compensated by chalcogen vacancies. It was established that in the lead sulfide, the only quasi-local energy level, being located in the valence band at the energy distance of 0.16 eV from its top, was connected with oxygen impurity. No other energy levels which one could connect with oxygen or with the complexes containing oxygen in lead sulfide was revealed. The storage stability of properties of investigated material was demonstrated.