Effect of Cd2+ Molar Concentration in CdxZn(1−x)S Thin Film by Chemical Bath Deposition Technique Using Alternative Sulfur Precursor

Abstract

Ternary semiconductor CdxZn(1−x)S thin films are prepared by chemical bath deposition (CBD) using N-methyl thiourea as an alternative sulfur precursor. Molar concentration of CdSO4 has been varied from 0.01 M to 0.09 M during the fabrication process of CdxZn(1−x)S thin film. Effect of variation in Cd2+ molar concentration on morphological, structural and opto-electrical properties of CdxZn(1−x)S thin film has been investigated. As grown films are found less crystalline and structural analysis suggests that CdxZn(1−x)S phase changes with the increase of Cd2+ molar concentration. SEM images reveals that all the films exhibit granules-like morphology. Raman peak indicates that higher concentration of CdSO4 precursor forms more CdS in the CdxZn(1−x)S. Bandgaps of CdxZn(1−x)S thin films are found to be ranged from 2.44 eV to 2.95 eV for different Cd2+ molar concentrations in the CdxZn(1−x)S thin films. Resistivity and carrier mobility of as grown CdxZn(1−x)S films ranged from 14.2 × 103 ohm-cm to 2.25 × 103 ohm-cm and 4.31 cm2 (V s)−1 to 9.42 cm2 (V s)−1, respectively. As all these findings affirms the credibility of using N-methyl thiourea as an alternative sulfur precursor for the development of CdxZn(1−x)S thin film by CBD process.