Electrical and optical properties of transparent conducting InxGa1-xN alloy films deposited by reactive co-sputtering of GaAs and indium

Abstract Thin films of In x Ga 1–x N alloys were deposited by reactive sputtering using a GaAs target, covered partially with indium and co-sputtered with nitrogen. X-ray and electron diffraction studies indicate the formation of single phase In x Ga 1–x N films at ~ 500 °C. Hall effect and resistivity measurements show that the alloy films with x ≥ 0.5 have high carrier concentrations in the range of 10 20 –10 21  cm − 3 and mobility of ~ 10 cm 2  V − 1  s − 1 . Optical measurements of the alloy films show a strong dependence of the band gap on carrier concentration, which is attributed to the Burstein–Moss shift and free carrier effects in the near-infrared region. The values of electron effective mass obtained from plasma resonance data and the Burstein–Moss shift show good agreement. Over a limited composition window of x in the range of 0.5–0.6, the alloy films exhibit low electrical resistivity (≈ 10 − 3  Ω-cm) and high transparency in part of the visible and near infrared regions, followed by high reflectance in the infrared region, which show their potential for applications as transparent electrodes in photovoltaic and photonic devices and as heat mirrors.