Effect of boron-doping on transparent conducting Al doped ZnO films for thin film solar cells

Al-doped ZnO (AZO) films with different boron (B) content have been prepared on glass substrates by co-sputtering of AZO (2wt. % Al2O3) and B-doped ZnO (BZO, 3wt. % B2O3) targets at room temperature. The B content in the B-doped AZO (BAZO) film was controlled by DC power on BZO target. X-ray diffraction analysis indicated that the B-doping improved the crystalline structure of AZO film. Hall measurement analysis showed that resistivity of BAZO films was lowered to 2.06×10⁻³ Ω·cm, whereas that of AZO film was 5.68×10⁻³ Ω·cm. Hall mobility of AZO film was improved with appropriate B-doping, and carrier concentration was increased with B-doping due to B activation as a donor.