High-concentration F-incorporated ZnO thin films doped via femtosecond-laser hyperdoping

Abstract

ZnO is a transparent conductive oxide that has received great attention over the past few decades, as it is a key component in light-emitting diodes, gas sensors, and solar cells. However, the electrical conductivity of intrinsic ZnO is not ideal, and thus, ZnO is often doped with appropriate elements such as fluorine (F). Unfortunately, the lack of adequate precursors in traditional doping methods may increase the difficulty of ZnO doping with F. In this work, we realized, for the first time, high-concentration F-doped ZnO thin films with a high Hall mobility of 20.7 cm2/V/s via femtosecond-laser hyperdoping. The highest atomic percentage of F was determined to be 8.3 at.%, which was over three times larger than that of previously reported F-doped ZnO films. Compared with pristine ZnO, the highest carrier concentration of the F-doped ZnO could be increased by four orders of magnitude, and the resistivity could be reduced by three orders of magnitude. Our results demonstrated that the femtosecond-laser hyperdoping technology could achieve efficient non-metallic hyperdoping of ZnO with high transparency and Hall mobility, thereby reducing the power dissipation and improving the current carrying capacity of ZnO-based devices.