Trapping levels in TlGaSe2 single crystals

• Charge trapping centers in TlGaSe2 were investigated using thermally stimulated current (TSC).
• Temperature dependent frequency factor and capture cross section are computed.
• Both TSC and the dark currents are measured in direction perpendicular to the layers..

Charge trapping centers in TlGaSe2 single crystals were investigated by the use of thermally stimulated current (TSC) technique. The measurements of TSC spectra in the temperature range from 90 K to 300 K were performed at a constant heating rate. The measurements showed that there are several trapping levels associated with the complex structure of overlapping peaks in the spectrum. The TSC spectra are dominated by two levels appeared at 204.1 K and 220.1 K. The experimental results indicate that the traps in TlGaSe2 associated with the spectra in the measuring range of temperature obey the monomolecular (first order) kinetics. Thus, the spectra are resolved into first order shaped peaks by the use of computerized best fit procedure. The trapping parameters, such as the energy depth, temperature dependent frequency factor and capture cross section together with the concentrations of the corresponding eight discrete levels, are computed. These centers all having high capture cross sections are found to be at the energies of 0.20 eV, 0.22 eV, 0.26 eV, 0.31 eV, 0.35 eV, 0.49 eV, 0.60 eV and 0.67 eV with low concentrations of 8.9 × 1013, 7.8 × 1013, 1.1 × 1014, 3.5 × 1013, 4.4 × 1013, 3.8 × 1013, 9.8 × 1014 and 8.8 × 1014 cm−3, respectively.