Effect of the copper content on the kinetics of the microwave photoconductivity of CIGS solid solutions

The kinetics of the photoresponse of microwave photoconductivity (9 GHz, TE$_{101}$-type cavity) on excitation by laser light pulses with a wavelength of 337 nm and a duration of 8 ns in copper-deficient Cu$_{1-x}$(In$_{0.7}$Ga$_{0.3}$)Se$_{2}$ (CIGS), 0 $<x\le$ 0.4 solid solutions with the chalcopyrite structure is investigated in a wide light intensity range. With an increase in the laser radiation density to $\sim$5 $\times$ 10$^{14}$ photon/cm$^2$ per pulse, the photoresponse acquires, along with the previously revealed skin effect, the effect of the filling of traps created by $V_{\operatorname{Cu}}$ vacancies and Cu$^{+2}$ $\cdot$ $V_{\operatorname{Cu}}$ defect associates, the concentration of which increases with a decrease in $x$ in the CIGS formula.