The effect of the annealing temperature and doping with cadmium on the deep trap levels in Cu2O is considered here. From photoluminescence and C-V (admittance spectroscopy) measurements it is demonstrated that in the energy gap of the undoped material there are deep traps at the energy levels 0.72, 1.19 and 1.33 eV from the valence band edge. Annealing of the samples in air at 500°C for 5 h decreases the concentration of the traps 1.19 and 1.33 eV, by a factor of 50. The origin of these two trap levels is singly and doubly ionized oxygen vacancies which are partially filled with the annealing. Doping with Cd decreases the trap concentration of these two trap levels by a factor of 7 and annealing of the doped material at 500°C in air removes completely these two trap levels. However, in the Cd-doped material a new trap appears at the energy level ∼0.90 eV from the valence band edge.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry