Optimization and characterization of remote plasma-enhanced chemical vapor deposition silicon nitride for the passivation of p-type crystalline silicon surfaces Plasma enhanced chemical vapor deposition and characterization of boron nitride gate insulators on InPRemote plasma enhanced chemical vapor deposition of silicon nitride on III-V semiconductors: Xray photoelectron spectroscopy studies of the interface J.

The direct capture of CO2 from ambient air presents a means of decelerating the growth of global atmospheric CO2 concentrations. Considerations relating to process engineering are the focus of this review and have received significantly less attention than those relating to the design of materials for direct air capture (DAC). We summarize minimum thermodynamic energy requirements, second law efficiencies, major unit operations and associated energy requirements, capital and operating expenses, and potential alternative process designs. We also highlight process designs applied toward more concentrated sources of CO2 that, if extended to lower concentrations, could help move DAC units closer to more economical continuous operation. Addressing shortcomings highlighted here could aid in the design of improved DAC processes that overcome trade-offs between capture performance and DAC cost. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

We report in this letter the observation of visible photoluminescence (PL) at room temperature from nanocrystallites embedded in hydrogenated amorphous silicon films, which are prepared in a plasma enhanced chemical vapor deposition system by using strong hydrogen-diluted silane as the reactant gas source, without any post-processing. The PL is attributed to the radiative recombination process of carriers in the nanocrystallites, and the quantum size effect is responsible for the emission above the band gap of bulk crystal Si. The critical deposition parameters of this type of film are identified.

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Plastic waste (PW) from textile and construction industries is rarely recycled due to the lack of economical and effective commercial recycling technologies. In this work, PW from these two sources is successfully converted into a microporous sorbent that is highly selective to carbon dioxide (CO2) adsorption. The synthesis of the sorbent is achieved by the pyrolysis of PW in the presence of a potassium salt activator. The properties of the sorbent can be tuned by changing the parent plastic type to get varying degrees of microporosity, surface area, and nitrogen content. The best performer, a sorbent derived from nylon 6,12, had a CO2 uptake of 19 wt% (4.32 mmol g−1) and 5 wt% (1.1 mmol g−1) at 1 and 0.1 bar, respectively. The initial estimated cost of synthesizing the sorbent is ≈$531 tonne−1 of PW making this process economically attractive compared to competitive technologies. The sorbent effectiveness in CO2 separation is demonstrated from various feeds including simulated flue gas and direct air capture. Thus, this upcycling approach can help to address two environmental challenges: PW pollution and increased atmospheric CO2 levels.