Terahertz properties of Tm (Tm=Cu, Ag) doped ZnO thin films

Optical properties of Zn$_{0.95}$Tm$_{0.05}$O (Tm=Cu, Ag) thin films are studied by terahertz time-domain spectroscopy (THz-TDS) at different temperatures (10K -- 300K) in the frequency range extending from 0.22 -- 3 THz. The measured complex dielectric response and conductivity are well fitted by a Drude-based model. Comparing with undoped ZnO thin films, the doping effect of Ag and Cu is investigated.