High-mobility sputtered F-doped ZnO films as good-performance transparent-electrode layers

ABSTRACT Point-defect engineering is an effective way to control the mobility and transparent-conducting performance of sputtered fluorine-doped ZnO (FZO) thin films. In this study, doping with fluorine (F) is accomplished through a simple one-step deposition process and is demonstrated to enhance the crystal quality, eliminate the point defects, and boost the mobility as well as the performance of the films. Furthermore, the films’ characteristics are observed to be strongly dependent on F content. At the optimum F content of 1%, the FZO films exhibited the best crystal quality and the lowest concentration of Zn interstitial and O vacancy defects due to F passivation. Moreover, a mobility as high as 45.3 cm2/Vs and the greatest figure-of-merit performance are achieved for cutting-edge transparent electrode applications. However, a further increase F content brought about an increased concentration of defects relating to Zn vacancies, especially F interstitials, and yielded low mobility and poor performance due to the degraded film structure.