Influence of Mg doping on electrical properties of Cu(In,Ga)Se2 bulk materials

•Mg-CIGSe at x = 0.1 achieves a hole content of ∼1016 cm−3 and mobility of ∼4 cm2/V s.•10% Mg doping can be good to modify the CIGSe properties for solar cells.•Electrical properties of Mg-CIGSe pellets are reported to change with the Mg ratios.•The Mg-to-Cu and Mg-to-In defects are proposed to explain electrical property.•Lattice constant data give the support of our proposing defect mechanism.

Mg-doped CIGSe bulk materials with the Cu0.9[(In0.7−xMgx)Ga0.3]Se2 formula at x = 0–0.15 were prepared at 650 °C. A two-step liquid-phase reaction sintering technique has been used in rather low temperature for the densification of Mg-doped CIGSe bulk materials with Sb2S3 and Te sintering aids. Electrical property was studied by measuring the mobility and concentration of charge carriers. All Mg-doped CIGSe pellets showed a p-type behavior. The favored low hole concentration of 2.86 × 1016 cm−3 and mobility of 4.23 cm2/V s were achieved for CIGSe materials doped with 10% of magnesium, as compared to 3.25 × 1016 cm−3 and 1.16 cm2/V s for undoped one. The explanations based upon the Mg-to-Cu antisite defect and the Mg-to-In defect for the changes in electrical property were declared. The study in bulk Mg-doped CIGSe has been based upon defect states and is consistent and supported by the data of lattice parameters.

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