Enhanced UV Photodetector Response of ZnO/Si With AlN Buffer Layer

Abstract

Studies have been carried out on the enhancement of responsivity and detectivity of the ZnO thin-films-based ultraviolet photodetectors by introducing an AlN buffer layer on silicon substrate. The ZnO film grown with AlN buffer layer established an epitaxial relation with the substrate and was found to show improved crystallinity with excellent optical properties. A strong and narrow photoluminescence emission was observed on the ZnO film grown with buffer layer, while a defect related broad emission was dominated on the film without buffer layer. The photodetectors showed a higher responsivity ( $R_{\lambda }$ ) of ${1.03} \times {10}^{{{{4}}}}$ A/W with a specific detectivity ( $D^{\ast }$ ) of ${5.21} \times {10}^{{{{12}}}}~ \text {cm}\cdot \text {Hz}^{{{{1/2}\cdot }}}\text {W}^{{{\text {-1}}}}$ at an applied bias of 3 V due to their excellent crystal quality.