Hydrothermally synthesized zinc oxide nanoparticle based photodetector for blue spectrum detection

A photodetector, based on zinc oxide nanoparticles (ZnO-NPs) is designed and fabricated using the drop casting method. Two glass slides coated with Indium tin oxide (ITO) thin films approximately 2.5 μm thick are used as source and drain electrodes, together with Schottky contacts fabricated with ZnO-NPs for the efficient transfer of photo-generated charge carriers. The proposed photodetectors showed significant sensitivity under white light emitting diode (LED) illumination at 468 nm, which is near the blue light spectrum. The current-voltage (I-V) characteristics of the proposed photodetectors indicate the generation of electron-hole pairs under white LED illumination at 265 μW, and stable photocurrent is achieved at high direct current (DC) bias voltages. Photodector response and recovery times of approximately 66.52 and 134.36 μs respectively are obtained at LED frequency modulation of 100 Hz at a bias voltage of 5 V. This represents an enhancement of the capabilities of ZnO-NPs, which is typically used for detection in the UV region only.