“…1a ). The composite phase structure and the corresponding stress fields could be the primary factor responsible for the enhancement of the diamond high-temperature oxidation resistance 24 , 37 , 38 . Fig.…”
Temperature is one of the seven fundamental physical quantities. The ability to measure temperatures approaching absolute zero has driven numerous advances in low-temperature physics and quantum physics. Currently, millikelvin temperatures and below are measured through the characterization of a certain thermal state of the system as there is no traditional thermometer capable of measuring temperatures at such low levels. In this study, we develop a kind of diamond with sp2-sp3 composite phase to tackle this problem. The synthesized composite phase diamond (CPD) exhibits a negative temperature coefficient, providing an excellent fit across a broad temperature range, and reaching a temperature measurement limit of 1 mK. Additionally, the CPD demonstrates low magnetic field sensitivity and excellent thermal stability, and can be fabricated into probes down to 1 micron in diameter, making it a promising candidate for the manufacture of next-generation cryogenic temperature sensors. This development is significant for the low-temperature physics researches, and can help facilitate the transition of quantum computing, quantum simulation, and other related technologies from research to practical applications.
“…1a ). The composite phase structure and the corresponding stress fields could be the primary factor responsible for the enhancement of the diamond high-temperature oxidation resistance 24 , 37 , 38 . Fig.…”
Temperature is one of the seven fundamental physical quantities. The ability to measure temperatures approaching absolute zero has driven numerous advances in low-temperature physics and quantum physics. Currently, millikelvin temperatures and below are measured through the characterization of a certain thermal state of the system as there is no traditional thermometer capable of measuring temperatures at such low levels. In this study, we develop a kind of diamond with sp2-sp3 composite phase to tackle this problem. The synthesized composite phase diamond (CPD) exhibits a negative temperature coefficient, providing an excellent fit across a broad temperature range, and reaching a temperature measurement limit of 1 mK. Additionally, the CPD demonstrates low magnetic field sensitivity and excellent thermal stability, and can be fabricated into probes down to 1 micron in diameter, making it a promising candidate for the manufacture of next-generation cryogenic temperature sensors. This development is significant for the low-temperature physics researches, and can help facilitate the transition of quantum computing, quantum simulation, and other related technologies from research to practical applications.
“…Under short-pulse laser irradiation, the diamond temperature rises sharply, making the C-C covalent bond broken and reconnected; three of the four outer valence electrons of each carbon atom 2 s, 2 px, 2 py in the form of sp2 hybridized orbitals in the same plane through the σ-bonding with three carbon atoms form a covalent single bond, with the orbitals between the central axis of the 120 • angle. The other 2 pz orbital electrons that are not involved in the hybridization are perpendicular to this plane and form unsaturated π-bonds in the pπ orbitals [26], as the diamond-graphitization transition occurs.…”
Section: Changes In the Properties Of Photoinduced Diamondmentioning
Laser-processing technology has been widely used in the ultra-precision machining of diamond materials. It has the advantages of high precision and high efficiency, especially in the field of super-hard materials and high-precision parts manufacturing. This paper explains the fundamental principles of diamond laser processing, introduces the interaction mechanisms between various types of lasers and diamond materials, focuses on analyzing the current development status of various modes of laser processing of diamond, briefly discusses the relevant applications in diamond cutting, micro-hole forming, and micro-groove machining, etc., and finally discusses the issues, challenges, and potential future advancements of laser technology in the field of diamond processing at this point.
“…[70][71][72][73] Hydrogen terminated sp 3 material present within grain boundaries is believed to form long-chain hydrocarbon polymers at 1800 to 2000 K, before C-H bond rupturing facilitates transformation to highly compressed sp 2 hybridized amorphous carbon, turbostratic carbon, and nanocrystalline graphite at 2100 K. [71][72][73][74] Concurrent graphitization, albeit to a lesser extent than that within grain boundaries, has meanwhile been shown to occur atop crystallite surfaces upon exceeding a temperature of 1700 K, with differing mechanisms either side of the Debye temperature of diamond due to differences in the excited lattice vibration modes; below 2021 K transformation occurs via the breaking of single C-C bonds, while beyond this point conversion is the result of rupturing of multiple C-C bonds, with a corresponding 2.4 fold increase in the associated activation energy. [75,76] As temperatures surpass 2200 K the graphitization process continues until the initial grain boundary is completely filled with more ordered material, before rapid transformation of grain cores from surrounding grain boundaries and crystallite surfaces. For ≈5 nm diameter dispersed nano-diamond particles in which the surface to volume ratio is greatly increased, lower activation energies result in the onset of this graphitization occurring at temperatures as low as 900 K. [63,77]…”
Micro‐hotplate structures are increasingly being investigated for use in a host of applications ranging from broadband infra‐red sources within absorption‐based gas sensors to in situ heater stages for ultra‐high‐resolution imaging. With devices usually fabricated from a conductive electrode placed on top of a freestanding radiator element, coefficient of thermal expansion (CTE) mismatches between layers and electro‐migration within the heating element typically lead to failure upon exceeding temperatures of 1600 K. In an attempt to mitigate such issues, a series of hotplates of varying geometry have been fabricated from a single layer of mechanically robust, high thermal conductivity, and low CTE boron‐doped polycrystalline diamond. Upon testing under high vacuum conditions and characterization of the emission spectra, the resulting devices are shown to exhibit a grey‐body like emission response and reach temperatures vastly in excess of conventional geometries of up to 2731 K at applied powers of ⩽100 mW. Characterization of the thermalization time meanwhile demonstrates rapid millisecond response times, while Raman spectroscopy reveals the performance of the devices is dictated by cumulative graphitization at elevated temperatures. As such, both diamond and sp2 carbon are shown to be promising materials for the fabrication of next‐generation micro‐hotplates.
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