Lifetime of excess electrons in Cu–Zn–Sn–Se powders

The investigation of the kinetics of the losses of nonequilibrium current carriers in Cu-=SUB=-2-delta-=/SUB=-NiSnS-=SUB=-4-=/SUB=- (0≤delta≤0.2) quaternary copper compounds

“…Literature data on the positions of peaks in Raman spectra are contradictory [9][10][11]. The positions of the most intense peaks in the measured Raman spectra (347 and 286 cm −1 ) are close to those given in [10].…”

“…where τ rec is the lifetime to recombination of localized electrons and free holes (recombination via local centers) and τ e and τ p are the times of thermal release of captured carriers from electron (A) and hole (B) traps, respectively. Thus, the estimated lifetimes to capture of photogenerated carriers in Cu 2−δ NiSnS 4 turned out to be shorter than the lifetimes for polycrystalline CZTS kesterites determined in our earlier microwave photoconductivity studies [11] and measured by the authors of [12] with the use of the timeresolved luminescence method. However, the lifetimes of carriers released back from traps are ∼ 7 ns and are comparable with literature data.…”

“…The lifetimes of carriers may then be estimated. If we assume that, in accordance with [10], k rec ∼ 10 −10 cm 3 • s −1 for a bandgap width of 1.2 eV [9] and k B = 10 6 cm −1 [11], lifetime τ e tr ≈ 0.03 ns. It is evident that the calculated time to capture of carriers is approximately 2 orders of magnitude shorter than the measured characteristic time of photoresponse decay.…”