Biphase effect on structural, optical, and electrical properties of Al-Sn codoped ZnO thin films deposited by sol-gel spin-Coating technique

Aluminum and tin codoped zinc oxide thin films were deposited on glass substrates by sol gel spin coating technique. Aluminum had a constant concentration of 2 at.% whereas tin was incorporated with different concentrations of 1, 2, 3, and 5 at.%. The prepared samples were polycrystalline and the grains growth was preferied along (002) orientation according to x-ray diffraction patterns. Transmittance analysis showed transparency over 80% in visible range for all samples and also the presence of two phases leading to two different optical band gaps in each sample. The amorphous phases had high optical band gaps and high Urbach energies compared to the crystalline phases. The resistivity measurements had revealed that the lowest resistivity value of about 1.65 x 10(-3)Omega.cm was obtained for Al 2 at.%, Sn 2 at.% concentration. These Al-Sn codoped ZnO thin films can have big interest in solar cell industry. Sample containing Al 2 at.%, Sn 1 at.% concentration was mainly amorphous and exhibited transparency over 60% in near ultraviolet region. Thereby, it may be promising to fabricate thin films transistors (TFTs) and ultraviolet light emitting diodes (UV-LEDs). (C) 2018 Published by Elsevier GmbH.