N-plasma modulation for boosting electromagnetic wave absorption behavior of MoO3 ceramic based on non-metallic doping

Abstract

Rational design and fabrication of MoO3 ceramic with controllable electronic structure is expected to deliver favorable magnetic moments, leading to excellent electromagnetic behavior. However, achieving large-scale precise modulation of the MoO3 electronic structure is still a challenge. Here, a low-temperature, high-efficiency nitrogen radio frequency (RF) plasma treatment method was adopted to modify the surface of MoO3 with N doping and investigate its electromagnetic wave absorption (EMA) mechanism in depth. After MoO3 powder treating with N2 plasma for 30 s, at the doping ratio is 70%, the minimum reflection loss (RLmin) is –43.35 dB and the maximum effective absorption bandwidth (EAB) could reach 6.16 GHz at a low thickness (2.1 mm). The significant improvements in dielectric loss and permeability loss of N-doped MoO3 are because the doping of N atoms reduces the bandgap of MoO3, promotes electron jumping, dramatically improves electrical conductivity of semiconductors, and introduces interfacial polarization and dipole polarization effects. The presence of magnetic moments renders the N-doped MoO3 with weak magnetic properties and significant eddy current losses. This study provides an explicit EMA mechanism for non-metal doped transition metal oxidation.