Enhanced ultraviolet (UV) photodetectors (PDs) with high responsivity comparable to that of visible and infrared photodetectors are needed for commercial applications. n-Type ZnO nanotubes (NTs) with high-quality optical, structural, and electrical properties on a p-type Si(100) substrate are successfully fabricated by pulsed laser deposition (PLD) to produce a UV PD with high responsivity, for the first time. We measure the current–voltage characteristics of the device under dark and illuminated conditions and demonstrated the high stability and responsivity (that reaches ∼101.2 A W–1) of the fabricated UV PD. Time-resolved spectroscopy is employed to identify exciton confinement, indicating that the high PD performance is due to optical confinement, the high surface-to-volume ratio, the high structural quality of the NTs, and the high photoinduced carrier density. The superior detectivity and responsivity of our NT-based PD clearly demonstrate that fabrication of high-performance UV detection devices for commercial applications is possible.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Tahani Flemban is grateful for a scholarship from Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia. The authors wish to thank Ms. Ecaterina Ware from Imperial College London, UK, for TEM sample preparation and Dr. M. A. Roldan from KAUST core lab for HR-TEM measurements. The authors thank KAUST for the financial support.