Influence of Cu content on the n → p transition of 15% Sn-doped Cux(In,Ga)Se2 bulk materials

• We studied the donor Sn-doped Cu(In,Ga)Se2 or CIGSe bulks at different Cu contents.
• Cu-less CIGSe is used to control carrier concentration but easily loss mobility.
• Sn doping here is to control the carrier concentration but keep high Cu content.
• By changing the Cu content, n- and p-type CIGSe with good properties were achieved.
• The CIGSe absorber shows the property diversity with the donor doping.

The elaborated Sn-doped Cu(In,Ga)Se2 (Sn-CIGSe) bulk materials with different Cu ratios had been sintered at 650 °C. Sn-CIGSe was reactively sintered with Sb2S3 and Te sintering aids. Electrical properties of Sn-CIGSe were measured and the variations in mobility, charge carrier density, and conductivity were rationalized. The Sn4+ donor in Cu-poor CIGSe favored the n-type behavior and the Cu deficiency increased electron concentration due to the formation of the indium-to-copper donor. The n → p transition for the Cu-rich Sn-CIGSe is related to the partial formation of the copper-to-indium and Sn2+ acceptor. Carrier mobility above 12 cm2/V s can be achieved for Sn-CIGSe with a higher Cu content. The advantages of Sn doping in CIGSe were claimed.

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