Enhancing the photosensitivity and photocatalytic performance of n-ZnO/p-ZnO:Sb homojunctions by titanium incorporation

Abstract

In this study, antimony-doped p-type ZnO and titanium-doped n-type ZnO thin films were prepared by chemical solution method. Homojunction structures have been successfully obtained between n-type ZnO and p-type ZnO thin films. Under UV light, measurements reveal that the addition of titanium raised the devices' photosensitivity from 66 to 3066. (a ∼4545 % improvement). The inclusion of titanium reduces the rise and descay times to 0.21 s. The dark currents of the devices were reduced from 2.14 nA to ultralow 0.06 nA by the introduction of titanium into the structure. The photoresponsivity and specific detectivity values of the devices were determined as (7.1 μA/W, 5.4 × 10⁷ Jones) and (9.2 μA/W, 4.2 × 10⁸ Jones) for undoped and titanium-doped devices, respectively. The photocatalytic performances of the prepared homojunction structures were also investigated. The photocatalytic efficiency of ZnO homojunctions increased by ∼10 % with the addition of titanium. The results obtained show that titanium plays a critical role in increasing the UV light sensitivity and photocatalytic performance of ZnO homojunction structures.