CdS-Decorated Al-Doped ZnO Nanorod/Polymer Schottky Junction Ultraviolet–Visible Dual-Wavelength Photodetector

Ultraviolet and visible dual-wavelength photosensing was observed using inorganic–organic Schottky junction. Photodetectors were fabricated by depositing dimethyl sulfoxide-modified poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) conducting polymer on CdS-decorated Al-doped ZnO nanorod arrays. A prominent dual-wavelength photosensitivity was observed at λ ≈ 380 nm and λ ≈ 500 nm with fast response and recovery time (∼20 ms) even at zero external bias. The maximum device performance was obtained at −5.0 V external bias with external quantum efficiency ≈ 55 864% and ∼12 590%; responsivity (Rλ) ≈ 171 and 50 A/W; detectivity (Dλ) ≈ 2.6 × 1011 and 7.7 × 1010 jones, corresponding to the wavelengths ∼380 and 500 nm, respectively. To protect from ambient atmosphere and moisture environment, the device was sealed with polydimethylsiloxane (PDMS) polymer. PDMS-encapsulated device demonstrated excellent photosensing behavior under water environment.