Structural, electrical and nonlinear optical characterization of Sn-doped CdO thin film synthesized via spray pyrolysis for optoelectronic applications

Transparent conducting metal oxides (TCOs) are well known for their application in optoelectronic devices. However, the nonlinear optical (NLO) study of TCOs helps to understand the characteristic features which give insight into their practical utilization as well as device application in each optical spectrum. In this work, we studied the structural, electrical, optical, and nonlinear optical properties of Sn-doped CdO. The structural, electrical, optical, and nonlinear optical properties of Sn-doped CdO were studied by using an X-ray diffractometer (XRD), Hall measurement system, UV–vis spectrometer, and Z-scan measurement. The XRD analysis shows that Sn-doped CdO is a polycrystalline material with a preferential peak of a plane (1 1 1) shifting slightly toward the (2 0 0) plane as Sn doping suddenly increases. Sn-doped CdO proved good electrical properties with conductivity increase from 0.192 × 10² Ω⁻¹ cm⁻¹ to 2.03 × 10² Ω⁻¹ cm⁻¹ and decrease in resistivity from 52.1 × 10⁻³ Ωcm to 4.92 × 10⁻³ Ωcm as the molar dopant concentration increase from 0.0001 M to 0.0005 M. The obtained bandgap for undoped and 0.0005 M, 0.0004 M, 0.0003 M, 0.0002 M, 0.0001 M Sn-doped CdO are 2.37, 1.63, 1.70, 1.81, 1.86, and 2.09 respectively. The NLO absorption coefficient (β) for 0.0003 M, 0.0004 M and 0.0005 M are 6.31 × 10⁻³ m/W, 11.47 × 10⁻³ m/W and 10.6 × 10⁻³ m/W respectively.