Spectral photoelectronic features of TlInSe2 single crystals

The nature of the photoconductivity (PC) in the TlInSe2 single crystals was elucidated by the implementation of the dc-PC method. The spectral distributions of the photocurrent were investigated in the photon energy range extending from 1.58 to 2.33 eV, and at the conditional working temperatures ranging from 77 to 300 K. However, the dc-PC measurements were carried out in light intensity of range 1200-4200 lx and bias voltage of range 8-28 V. Accordingly, the temperature dependence of the energy gap was studied and analyzed. The photosensitivity was also calculated in different levels of illumination, F = 1.1ϕ, 1.4ϕ, 1.7ϕ, 2ϕ, 2.3ϕ and 2.6ϕ, where ϕ = 1000 lx. The recombination process of the photo-carriers was determined to be attributed to a continuous distribution of defect states in the gap. However, the steady-state photoconductivity study showed that the recombination process in mentioned crystals occurred as a result of a continuous distribution of impurity states. Finally, the transient behavior of photoconductivity in the TlInSe2 single crystals was investigated in all the aforementioned levels of illumination. Accordingly, the crystals under study exhibit a non-exponential decay of PC and the decay processes were investigated in line with the concept of differential lifetime.