High-performance IGZO/Ga2O3 dual-active-layer thin film transistor for deep UV detection
Zuyin Han, Shuang Song, Huili Liang, Hang Shao, Sigui Hu, Yan Wang, Jiwei Wang, Zengxia Mei
Abstract
Owing to the intrinsically wide bandgap and high uniformity, amorphous Ga2O3 (a-Ga2O3) has been illustrating a great industrial potential for large-area deep ultraviolet (UV) photosensor arrays. However, a seemingly irreconcilable contradiction between high responsivity and long persistent photoconductivity has hampered the growing pace of such devices. In this work, three-terminal InGaZnO (IGZO)/a-Ga2O3 dual-active-layer (DAL) transistors were developed to realize the ability of a-Ga2O3 as the active layer both in switching and sensing. Benefitting from the introduction of ultrathin IGZO electron reservoir and defect control of a-Ga2O3, the DAL device demonstrates more stable and superior gate-control capability with promising performance including high on/off ratio and field-effect mobility of ∼108 and 8.3 cm2/V⋅s, respectively, as well as a small sub-threshold swing (SS) of 0.36 V/dec. Under 254 nm UV illumination, the DAL device manifests a light-to-dark ratio of ∼108, a responsivity of 4.8 × 103 A W−1, a detectivity of 8 × 1015 Jones, and a UV/visible rejection ratio (R254/R400) of 64. The simultaneous achievement of deep UV photo-detection and transistor's switching performance in a-Ga2O3 material offers excellent potential for the construction of large-area active-matrix UV photosensor arrays with the simple and low-cost fabrication process.