Stable Sn-doped In2O3 films coated on Al2O3 for infrared transparent and electromagnetic shielding conductors

The transparency of most electromagnetic shielding conductors is limited to the visible regime. Here, we demonstrate the high infrared transmittance (>50% at 4-μm-wavelength), low sheet resistance (<200 Ω □−1 at room temperature), and high shielding effectiveness (∼16.2 dB at 10 GHz for the X-band) of 20–90-nm-thick Sn-doped In2O3 films deposited on an (0001)-oriented Al2O3 substrate. The phase persists even at 700 °C in air. Thus, multifunctional Sn-doped In2O3 films on Al2O3 substrates will advance technology in the areas of military applications, invisible circuitry, smart windows, infrared sensors, and transparent solar cells working in extreme environment.