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    Superschnelle, mit Diamanten besetzte Computerchips dank „Quantendurchbruch“ jetzt viel näher an der Realität


    Superschnelle, mit Diamanten besetzte Computerchips dank „Quantendurchbruch“ jetzt viel näher an der Realität

    https://www.livescience.com/technology/electronics/superfast-diamond-laced-computer-chips-now-much-closer-to-reality-thanks-to-quantum-breakthrough

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    1. Vailhem on

      Quantum chemistry model of surface reactions and kinetic model of diamond growth: Effects of CH3 radicals and C2H2 molecules at low-temperatures CVD – Nov 2024

      https://www.sciencedirect.com/science/article/abs/pii/S0925963524007908?via%3Dihub

      …

      Abstract

      > The objective of this study is to explore conditions that facilitate a significant reduction in substrate temperature during diamond growth.

      > The typical temperature for this process is around 1200 K; we aim to reduce it to a much lower level.

      > To achieve this, we need to understand processes that limit the diamond growth at low temperatures.

      > Therefore, we developed a detailed chemical kinetic model to analyze diamond growth on the (100) surface.

      > This model accounts for variations in substrate temperature and gas composition.

      > Using an ab initio quantum chemistry, we calculated the reaction rates of all major gas phase reactants with the diamond surface, totaling 91 elemental surface reactions.

      > Based on this comprehensive model, we developed a reduced model consisting of 8 reactions.

      > This reduction enabled us to derive an analytical equation that describes the rate of diamond growth across a broad range of temperatures involving CH3, H, H2, and C2H2 reactants.

      > Consistent with previous studies, the model identifies that CH3 is a major precursor of diamond growth, and the contribution from C2H2 to the growth is significantly smaller.

      > However, C2H2 can also contribute to forming a sp2-phase instead of a sp3-phase, and this process becomes dominant below a critical temperature.

      > As a result, C2H2 flux inhibits diamond growth at low temperatures.

      > To quantify this deleterious process, we developed a new mechanism for sp2-phase nucleation on the (100) surface.

      > Similar to the so-called HACA mechanism for soot formation it involves hydrogen abstraction and C2H2 addition.

      > Consequently, optimal low-temperature CVD growth could be realized in a reactor designed to maximize the CH3 radical production, while minimizing the generation of C2H2 and other sp. and sp2 hydrocarbons.

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