Abstract 

 A novel doping technique with an initiated chemical vapor deposition (iCVD) process is applied to fabricate aluminum (Al)-doped zinc oxide (ZnO) channel thin-film ultraviolet (UV) phototransistor (PT). The iCVD doping technique can successfully introduce Al throughout the ZnO channel without any surface damage. The sub-bandgap states mainly due to oxygen vacancy (VO) defects in the ZnO channel are effectively suppressed by Al doping; the subthreshold swing of the PT has been reduced by more than half to 168 mV/dec and under negative gate bias illumination stress, the threshold voltage shift is reduced by about half to -2.03 V, which improves the reliability. For the UV detection, the Al-doped ZnO PT exhibits a high responsivity of 358.93 A·W-1, an ultra-high UV-to-visible rejection ratio of 4.81 × 10^​6, a high detectivity (D*) of 1.68 × 10^​15 Jones, a low noise equivalent power of 2.98 × 10^​-18 W·Hz-1, and fast switching performance. The developed Al-doped ZnO PT can be used in low cost and high performed UV detection for various applications.