Highly efficient field emission from indium-doped ZnO nanostructure on nanographene/macroporous electric conductive network

Indium-doped ZnO nanoparticles coated on nanographene/MECN enhance the field emission properties by avoiding electrostatic screen, providing more emitters, as well as introducing nanographene and indium doping. A simple hydrothermal method is developed to fabricate In-doped ZnO field emitters with different ratios of In and ZnO (5%, 10%, and 20%). The 10% In-ZnO shows a turn-on electric field as low as 1 V·μm⁻¹ at a current density of 10 μA·cm⁻², and the threshold field is 5.8 V·μm⁻¹ at 1 mA·cm⁻². The largest current density is 2.88 mA·cm⁻², and the estimated β is 27918. The emission currents are very stable at high, medium, and low current densities with an average deviation of only 2.5%. The outstanding field emission performance indicates that In-doped ZnO coated on nanographene/MECN is an efficient field emitter and has large potential in displays, lightings, and sensors.