Cu(In,Ga)Se2 (CIGS) ince filmlerin sol-jel tekniğiyle büyütülmesi, karakterizasyonu ve beta ışınlarının etkisinin incelenmesi

One of the most promising absorber material for the thin-film solar modules is polycrystalline chalcopyrite thin-film solar cell based on Cu(In, Ga)Se2 (CIGS) by having the direct energy band gap and high absorption coefficient. CIGS compounds have high solar to electricity conversion efficiency, reliability and stability. Solar cells using CIGS as an absorber block, having a direct band gap within the maximum solar absorption region, a high absorption coefficient (105 cm-1) and appropriate electrical and optical properties for production, as has been demonstrated by the ~ 20% conversion efficiency. Cu(In,Ga)Se2 (CIGS) thin-films were prepared by economical sol–gel dip coating technique of aqueous solution of Cu(NO3)2·3H2O, In(NO3)2·3H2O, Ga(NO3)3·H2O and SeO2 onto soda-lime silicate glass substrates. Sol–gel dip coating technique is the most economical way for depositing CIGS thin-films by utilizing a non-vacuum technology and involving cheap equipments and lower temperature. The optimum optical properties of CIGS thin-films is obtained by varying the film thickness. Beside that, the sol-gel derived CIGS thin-films with determined thickness were thermally treated at different temperatures from 135 °C up to 200 °C with a colloidal solution prepared in an air ambiance under the standard laboratory conditions and in an inert atmosphere. The ultra CIGS thin-films deposited from the colloidal solution prepared under argon gas exhibit quasi-amorphous structure while in air ambiance it was amorphous structure. Cu(In,Ga)Se2 thin-films were deposited at different pH-values changing from 1 to 4 by using sol-gel dip coating technique at 150 oC annealing temperature, in an air ambiance. The structural, optical and electrical properties were investigated for the different pH-values to determine the optimum pH-value. The optimum optical properties for the use of a potential absorber material depending on its favorable energy band gap (~ 1.6 eV) and optimum electrical conductivity is obtained by controlling the pH-value of the CIGS solution between 1.5-2.0 pH. These results indicate that the CIGS thin-films obtained by sol-gel process can be good candidates for applications in optoelectronic devices. The effect of ionization radiation on the optical materials is promising in the radiation science and air & space science. The ionized radiation causes changes at the physical and chemical properties with exciting the free carriers and forming the electron-hole pairs. The irradiation effect on the CIGS thin-films is evaluated by determining optical energy band gap of the films exposed to the beta radiation source by using Sr-90 radioisotope. The variations in structural, optical and electrical properties were considered with respect to the absorbed dose level to investigate the characteristic properties of CIGS thin-films. The observed effects in electrical resistivity are attributed to beta irradiation-induced formation of defects in the CIGS thin-film structure. The significant blue shift of absorption edge was improved by beta irradiation with the reduced elapsed time of colloidal solution and the increased of thickness. The irradiation treatment was conducted by using Sr-90 radioisotopes which played an important role in enhancing electrical properties. The beta irradiation was a key parameter to decrease the electrical resistivity of CIGS thin-film.