Electrical and UV detecting investigation of the ZnO nanorods encapsulated with ZnO and Fe-doped ZnO

Abstract

Encapsulated ZnO nanorod arrays were fabricated by a two-step method, hydrothermal followed by dip coating. The peaks intensity of ZnO nanorod film encapsulated with ZnO layer increased whereas it slightly decreased for that encapsulated with Fe doped ZnO layer. The peak position of the samples was not affected by encapsulating process and or Fe dopant. The encapsulating process increased the rods diameter in a range of 20-40 nm. Optical studies indicated a reduction in band gap of encapsulated nanorods. The current-voltage characteristics of the sensors at room temperature illustrated remarkable reduction in resistance due to encapsulation process especially in the encapsulated ZnO nanorod film with Fe doped-ZnO layer. The photoresponse variations of all the sensors were investigated under different powers of UV illumination and it was found that the nanorods have high sensitivity to UV light. The rise/recovery time changed from 92/202 to 20/126s, for bare and encapsulated nanorod, respectively. Responsivity was seen to increase from 0.6 to 16 when nanorods were encapsulated with 0.5 at% Fe doped-ZnO layer.