Influence of bath temperature on surface modification and optoelectronic properties of chemical bath deposited CdS thin film nanostructures

Highlights: • Honey comb (hexagonal Phase) and seaweed (cubic Phase) like CdS nanostructures synthesized from Chemical bath deposition by varying bath temperature. • Surface morphology, crystal structure shows strong dependence with temperature. • An enhanced photoluminescence, especially green band emission observed with the increase in bath temperature. • Found that band gap can be tuned by varying bath temperature. • An enhanced persistent photoconductivity observed with increase in temperature. -- Abstract: Cadmium sulfide thin film nanostructures with various surface morphologies were synthesized using chemical bath deposition method (CBD) by varying bath temperature. Samples deposited at room temperature shows surface morphology similar to 'seaweed' pattern that crystallized in cubic structure, whereas those deposited at higher temperatures exhibit 'honeycomb' like surface pattern with hexagonal crystal structure. HRTEM images of the honeycomb structure shows that, nanowalls consist of CdS nanoparticles embedded with cadmium hydroxide just like 'plum in pudding'. An improvement in conductivity and photosensitivity observed with increase in bath temperature. Photoluminescence measurements show that there are five emission peaks falls in green, red and infrared bands. The intensity of photoluminescence emission in the green band region found to be increased on thin films that deposited at elevated temperatures. Unique honeycomb like structures observed at 65 °C, shows comparatively high performance in structural and optoelectronic properties give it a slight edge in optoelectronic application.