Carrier transport characteristics of H-terminated diamond films prepared using molecular hydrogen and atomic hydrogen

The H-terminated diamond films, which exhibit high surface conductivity, have been used in high-frequency and high-power electronic devices. In this paper, the surface conductive channel on specimens from the same diamond film was obtained by hydrogen plasma treatment and by heating under a hydrogen atmosphere, respectively, and the surface carrier transport characteristics of both samples were compared and evaluated. The results show that the carrier mobility and carrier density of the sample treated by hydrogen plasma are 15 cm^2·V^（-1）·s^（-1） and greater than 5 × 1012 cm^（-2）, respectively, and that the carrier mobilities measured at five different areas are similar. Compared to the hydrogen-plasma-treated specimen, the thermally hydrogenated specimen exhibits a lower surface conductivity, a carrier density one order of magnitude lower, and a carrier mobility that varies from 2 to 33 cm^2·V^（-1）·s^（-1）. The activated hydrogen atoms restructure the diamond surface, remove the scratches, and passivate the surface states via the etching effect during the hydrogen plasma treatment process, which maintains a higher carrier density and a more stable carrier mobility.

Electrical stress and acid orange 7 synergistically clear the blockage of electron flow in the methanogenesis of low-strength wastewater

Energy recovery from low-strength wastewater through anaerobic methanogenesis is constrained by limited substrate availability.The development of efficient methanogenic communities is critical but challenging.Here we develop a strategy to acclimate methanogenic communities using conductive carrier(CC),electrical stress(ES),and Acid Orange 7(AO7)in a modified biofilter.The synergistic integration of CC,ES,and AO7 precipitated a remarkable 72-fold surge in methane production rate compared to the baseline.This increase was attributed to an altered methanogenic community function,independent of the continuous presence of AO7 and ES.AO7 acted as an external electron acceptor,accelerating acetogenesis from fermentation intermediates,restructuring the bacterial community,and enriching electroactive bacteria(EAB).Meanwhile,CC and ES orchestrated the assembly of the archaeal community and promoted electrotrophic methanogens,enhancing acetotrophic methanogenesis electron flow via a mechanism distinct from direct electrochemical interactions.The collective application of CC,ES,and AO7 effectively mitigated electron flow impediments in low-strength wastewater methanogenesis,achieving an additional 34%electron recovery from the substrate.This study proposes a new method of amending anaerobic digestion systems with conductive materials to advance wastewater treatment,sustainability,and energy self-sufficiency.