Photoresponse characteristics of aluminum doped zinc oxide thin film

Abstract

The paper investigates the influence of different aluminum doping concentration on the photoresponse characteristics of doped ZnO thin films. Aluminum doped ZnO (AZO) thin films have been prepared by sol-gel dip-coating technique on glass substrates. 0.4M sol of AZO were prepared using monoethanolamine (MEA) as the stabilizer, zinc acetate dehydrate (Zn(CH3COO)2.2H2O) as the precursor, 2-methoxyethanol as solvent and aluminum nitrate nanohydrate (Al(NO3)3.9H2O) as dopant source. Samples with different weight percentage of the dopant were prepared to study the effect to electrical and optical properties of the thin films in dark and under illumination conditions. Electrical properties of thin films were characterized using 2-probe Current-Voltage (I-V) measurement system (Advantest R6243). The optical properties were studied using UV-Vis-NIR spectrometer. The electrical properties of the AZO thin films show higher conductivity under illumination compared to in dark condition. The optical properties show that the optical bandgap of the thin films increases with the increment of the doping concentrations.