Photoelectric and x-ray dosimetric properties of TlGaS₂〈Yb〉 single crystals

Abstract

The photoelectric properties of TlGa₁₋ xYb_xS₂ (x = 0, 0.01) single crystals are investigated. It is established that partial substitution of ytterbium for gallium leads to (i) an increase in the electrical resistivity of the samples, (ii) a shift in the maximum of the intrinsic photocurrent toward the long-wavelength range of the spectrum, (iii) a considerable broadening of the spectral sensitivity range, and (iv) an increase in the amplitude of the extrinsic photocurrent. Analysis of the x-ray dosimetric characteristics of the TlGa 1−xYb_xS₂ single crystals demonstrates that, upon partial substitution of ytterbium for gallium in TlGaS₂, the x-ray sensitivity coefficient increases significantly and the current-dose characteristics ΔI E, 0 ∼ E ^α tend to linearity (α = 1) at low dose rates (E, R/min) of soft x rays. At high dose rates of hard x rays, α tends to 0.5 for both undoped and ytterbium-doped TlGaS₂ single crystals.