Fabrication and characteristics of photodiode based on ZnO nanowire arrays and spray-coated regioregular P3HT layers

A photodiode based on well-aligned ZnO nanowire arrays (ZNAs) and spray-coated regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) layers hybrid hetero junctions was fabricated, and its electrical characteristics in dark and under illumination with a solar simulator were investigated. Current–voltage (I–V) data of ITO/ZNAs/P3HT/Ag device in dark and under illumination showed typical diode characteristics. A rectification ratio (RR) of 22.7 at 1.7 V and a low turn-on voltage of 0.4 V in dark were obtained. Also, the photodiode with high photo-response in the order of 0.31 A/W at -2 V using 80 mW/cm2 illumination power was observed. Upon increasing illumination power from 40 to 100 mW/cm2, the RR value for the photodiode continuously was improved with a highest value of 12.5.

► Well-aligned ZnO nanowire arrays were synthesized at low temperature.
► Regioregular P3HT layer was deposited by low-cost spray coating technique.
► The photodiode has good rectifying properties in dark and under illumination.
► The photodiode has high photo-response.