Influence of Reactive Ion Etching on THz Transmission and Reflection Properties of NiCr Film Deposited on a Dielectric Substrate

摘要： Enhanced terahertz (THz) absorption of NiCr film deposited on a dielectric substrate has been proven by applying a reactive ion etching (RIE) treatment to the dielectric film. Nano-scale nickel-chromium (NiCr) thin films are deposited on RIE treated silicon dioxide (SiO2) dielectric substrates to study the transmission and reflection characteristics. Experimental results suggest that both transmission and reflection of NiCr film are weakened by the RIE treatment. The most significant decrease of transmission is observed in (1 ~ 4) THz while that of reflection occurs in (1.7 ~ 2.5) THz band. The decrease of both transmission and reflection is more significant for NiCr film with higher thickness. The RIE treatment, which induces a roughened surface of SiO2 substrate and increases the effective surface area of NiCr film, enhances the absorption and weakens the transmission and reflection of THz radiation.