Strong Microwave Absorption of Hydrogenated Wide Bandgap Semiconductor Nanoparticles

Abstract

Electromagnetic interactions in the microelectronvolt (μeV) or microwave region have numerous important applications in both civil and military fields, such as electronic communications, signal protection, and antireflective coatings on airplanes against microwave detection. Traditionally, nonmagnetic wide-bandgap metal oxide semiconductors lack these μeV electronic transitions and applications. Here, we demonstrate that these metal oxides can be fabricated as good microwave absorbers using a 2D electron gas plasma resonance at the disorder/order interface generated by a hydrogenation process. Using ZnO and TiO2 nanoparticles as examples, we show that large absorption with reflection loss values as large as -49.0 dB (99.99999%) is obtained in the microwave region. The frequency of absorption can be tuned with the particle size and hydrogenation condition. These results may pave the way for new applications for wide bandgap semiconductors, especially in the μeV regime.

Modifying oxide nanomaterials’ properties by hydrogenation

“…[77,78] This discovery has been expanded to hydrogenated ZnO and BaTiO 3 nanoparticles for enhanced microwave absorption. [80,81] Hydrogenated TiO 2 nanoparticles have recently been demonstrated with promising medical application due to their extended absorption in the infrared region. [82,83] They can efficiently convert the near-infrared light energy into thermal energy and produce localized heat island.…”

“…[81,[84][85][86][87][88][89][90][91][92] Here, only some recent works are given as examples. Similar to hydrogenation on TiO 2 , hydrogenation introduces visible-light absorption, [86] oxygen vacancies, [86] zinc vacancies, [86,91] interstitial hydrogen, [84,85] and increased carrier densities.…”

“…[90] Similar to hydrogenated TiO 2 , hydrogenated ZnO also displays impressive microwave absorption performance. [81] In addition, hydrogenation seems to have a large impact on the ferromagnetism of ZnO nanoparticles. [91] Hydrogenated ZnO nanoparticles display room-temperature ferromagnetism and their ferromagnetism can be switched between "on" and "off" by annealing in hydrogen or oxygen, respectively.…”

Synthesis and Excellent Microwave Absorption Properties of ZnO/Fe3O4/MWCNTs Composites

“…Semiconductors materials have recently attracted considerable interest as electromagnetic (EM) wave absorption and EM interference shield materials within the GHz frequency range because of their unique chemical and physical properties, such as SnO 2 , 1-3 TiO 2 , [4][5][6] SiC, 7,8 and ZnO. 9,10 As a wide-band-gap (E g ¼ 3:37 eV) semiconductor, ZnO has been intensively studied because of its wide applications in sensors, [11][12][13][14] solar cells, [15][16][17][18] and photocatalytic materials.…”

The Optimization of Switching Scheme in Multi-Layer Phase-Modulated Surface and Its Influence on Scattering Properties

“…Due to its unique electromagnetic property, PMS was used to reduce the RCS of spiral patch antenna [13], generated SSB or QPSK modulation signal [14,15] and lowered the power spectral density (PSD) of echo scattered from PMS [16]. Besides PMS, several new techniques or materials have been proposed for the design of active RAM in the past few years, e.g., graphene-enabled electrically switchable radarabsorbing surfaces relying on electrostatic tuning of the charge density on an atomically thin graphene electrode [17], inkjet printing technology in which the volume ratio of an aqueous vehicle and nanosilver (Ag) ink mixture is adjusted to change the surface resistances [18] and semiconductor nanoparticles whose particle size and hydrogenation condition are connected with its electromagnetic characteristic [19], etc.…”