Effects of substrate temperature on the structural, morphological, electrical and optical properties of Al and Ga co-doped ZnO thin films grown by DC magnetron sputtering

• AGZO thin films were deposited at different substrate temperatures.
• The average grain size increased from 20.6 nm to 51.4 nm.
• The RMS surface roughness decreased from 21.1 nm to 4.0 nm.
• The film deposited at 350 °C exhibited a lowest resistivity of 3.0×10−4 Ω cm.

In this work, Al and Ga co-doped zinc oxide (AGZO) thin films were deposited on glass substrates by DC magnetron sputtering under different substrate temperatures. Evolutions of the structural, morphological, electrical and optical properties of the AGZO thin films as a function of substrate temperature were analyzed. Results showed that the average transmittance in the visible range (400–800 nm) for all the thin films was over 82%, which did not change obviously with the substrate temperature. The average grain size increased from 20.6 nm to 51.4 nm and the RMS surface roughness decreased from 21.1 nm to 4.0 nm with substrate temperatures ranging from 150 °C up to 450 °C. The carrier concentration, Hall mobility of the thin films increased when the substrate temperature was increased from 150 °C to 350 °C, and then decreased with a further increase of substrate temperature. The film deposited at 350 °C exhibited a lowest resistivity of 3.0×10−4 Ω cm with the highest carrier concentration of 5.0×1020 cm−3 and Hall mobility of 42 cm2 V−1 s−1.