WANG Xiaojing1,2,LEI Qingsong1,YUAN Junming1,ZHOU Wenli1,2*,YU Jun1,2 (1. Department of Electronics Science & Technology,Huazhong University of Science & Technology,Wuhan 430074,China,2. Hubei PV Center of Engineering&Technology,China)
Abstract:
Aluminium doped ZnO thin films(ZnO:Al) were deposited on transparent polymer substrates at room temperature by rf magnetron
sputtering method from a ZnO target with Al2O3 of 2.0 wt%. Argon gas pressure varied from 0.5 Pa to 2.5 Pa with radio frequency power of 120 W. XRD results showed that
all the ZnO:Al films had a polycrystalline hexagonal structure and a (002) preferred orientation with the c-axis perpendicular
to the substrate. The grain sizes of the films were 6.3–14.8 nm.SEM images indicated the ZnO:Al film with low Argon gas pressure
was denser and the deposition rate of the films depended strongly on the Argon gas pressure, increasing firstly and then decreasing
with increasing the pressure. The highest deposition rate was 5.2 nm/min at 1 Pa. The optical transmittance of the ZnO:Al
films increased and the blue shift of the absorption edge appeared when the Argon gas pressure increased. The highest transmittance
of obtained ZnO:Al films at 2.5 Pa was about 85% in the visible region. The electrical properties of the films were worsened
with the increase of the Argon gas power from 1 Pa to 2.5 Pa. The resistivity of obtained film at 1.0 Pa was 2.79 ×10?2 Ω·cm.